This Slow Cooker Chicken Casserole is the ultimate comfort food for a cold day when you want something warming. Tender chicken thighs, chunky vegetables and potatoes are cooked slowly in a creamy mustard and herb sauce until everything is soft, comforting and full of flavour.
There is no browning and no pre-cooking, so once everything is chopped it can go straight into the slow cooker. I can get it started before the afternoon gets hectic and then all I need to do before dinner is stir through the crème fraîche and parsley.
It's a complete meal in one pot, but a chunk of crusty bread for mopping up the creamy sauce is highly recommended. My kids happily eat vegetables in this that they wouldn't usually eat, and I put that down to the incredible creamy sauce.
Recipe update: This recipe was originally published on 27 September 2020 and was fully retested in October 2026 to check the cooking time and ingredient quantities. The original recipe still worked well, but I've expanded the instructions, tips and FAQs.
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Jump to:
- Why You'll Love It
- Recipe Overview
- Ingredients and Substitutions
- How to Make Slow Cooker Chicken Casserole
- How Long Does Chicken Casserole Take in the Slow Cooker?
- Chicken Thighs or Chicken Breast?
- Variations
- How to Thicken Slow Cooker Chicken Casserole
- Serving Suggestions
- Storage
- Troubleshooting Guide
- Dannii's Top Tips
- Frequently Asked Questions
- More Slow Cooker Chicken Recipes
- Recipe
- Feedback
Why You'll Love It
- Proper comfort food - tender chicken and chunky vegetables in a creamy, herby mustard sauce.
- No browning needed - everything goes straight into the slow cooker, making this an easy chicken casserole for busy days.
- A complete one-pot dinner - chicken, potatoes and plenty of vegetables all cook together.
- Family friendly - the mustard adds flavour without making the sauce spicy.
- Great for batch cooking - leftovers keep well and the casserole can be frozen.
- Protein packed - each serving provides around 35g of protein as well as 5g of fibre.
Recipe Overview
- Prep time: 15 minutes
- Cook time: 4 hours on HIGH
- Serves: 4
- Main ingredient: Boneless skinless chicken thighs
- Flavour: Creamy, herby, savoury mustard sauce
- Difficulty: Easy
- Prep style: No browning or pre-cooking
- Freezer friendly: Yes
Ingredients and Substitutions
A full ingredients list, along with US Customary and Metric measurements, can be found in the recipe card at the end of this post.
- Chicken thighs - Boneless, skinless chicken thighs are my first choice for a slow cooker chicken casserole. They stay juicy and tender after several hours of cooking and have more flavour than chicken breast.
- Shallots - These add a lovely sweetness and I like leaving small shallots whole or just cutting larger ones in half. A chopped brown onion works too.
- Leek - Leek gives the casserole a mild sweetness and works really well with the chicken and creamy mustard sauce. Make sure you wash it thoroughly between the layers before slicing.
- Carrots and celery - These form the vegetable base of the casserole. I keep the carrots fairly chunky so they don't become too soft during cooking.
- New potatoes - Adding potatoes makes this a full meal without needing another side. Baby or new potatoes are ideal; halve larger ones so everything cooks evenly.
- Mushrooms - Button mushrooms add extra bulk and savoury flavour. Leave smaller mushrooms whole or halve larger ones so they keep some texture.
- Garlic and herbs - Garlic, thyme and oregano give the stock plenty of flavour without needing a long ingredient list.
- Chicken stock - You only need 200ml. It might not look like much, but the chicken and vegetables release liquid while they cook, so adding too much stock can leave you with a watery casserole.
- Wholegrain mustard - This gives the sauce a gentle tang without overpowering it. Dijon mustard is a good alternative.
- Crème fraîche - Stirred through at the end, this turns the cooking liquid into a creamy sauce. Reduced-fat crème fraîche works too, or you can use thick double cream.
- Fresh parsley - Add this at the end for freshness and colour.
More ways to adapt this recipe can be found in the Variations section below.
How to Make Slow Cooker Chicken Casserole
- Add the vegetables: Put the shallots, leek, mushrooms, carrots, celery and potatoes into the slow cooker. Keep the carrots and potatoes towards the bottom, where they will be closest to the heat and cooking liquid.
- Add the chicken: Place the chicken thighs on top of the vegetables.
- Add the liquid: Mix together the chicken stock, garlic, wholegrain mustard, thyme, oregano, salt and pepper. Pour it over the chicken and vegetables.
- Cook: Put the lid on and cook on HIGH for 4 hours or LOW for 6-7 hours, until the vegetables are tender and the chicken is cooked through.
- Pull the chicken: Remove or gently pull apart the chicken and shred it into large chunks. I prefer keeping some bigger pieces rather than shredding it very finely.
- Add the crème fraîche and parsley: Add the crème fraîche and chopped parsley.
- Check and serve: Carefully stir everything together. Taste and adjust the seasoning before serving.
How Long Does Chicken Casserole Take in the Slow Cooker?
This recipe takes 4 hours on HIGH or 6-7 hours on LOW.
Chicken thighs are more forgiving than chicken breasts, and stay fairly juicy even if you cook them a little longer. But you don't want to overcook them.
Chicken Thighs or Chicken Breast?
Chicken thighs are my preference for this casserole because they stay juicy and tender during slow cooking. They also have more flavour, which works particularly well in a simple creamy sauce.
You can make slow cooker chicken casserole with chicken breast, but breast is leaner and can become dry or stringy if it is cooked for too long.
If chicken breast is what you have, I would keep the pieces fairly large and start checking them earlier rather than automatically giving them the full cooking time.
If you want to cook chicken breast in the slow cooker, check out my Slow Cooker Chicken Breast recipe.
Variations
This is one of those recipes I often use to clear out the vegetable drawer, so don't worry if you don't have every vegetable listed.
You could add parsnip, swede, butternut squash or sweet potato in place of some of the potatoes and carrots. Keep root vegetables fairly chunky so they don't disappear into the sauce.
For an extra green vegetable, stir through a couple of handfuls of spinach just before serving.
If you particularly love chicken and leek casserole, add a second leek and reduce the shallots slightly.
For more of a chicken and mushroom casserole, increase the mushrooms to around 200-250g and use chestnut mushrooms for a deeper flavour.
Chopped cooked bacon or ham can also be stirred through at the end for a saltier, smokier version.
How to Thicken Slow Cooker Chicken Casserole
Slow cookers hold on to moisture, so sauces do not reduce in the same way they would in an uncovered pan.
Start with the 200ml of stock in the recipe and resist the temptation to add more. You don't need as much liquid as you might think.
After stirring in the crème fraîche, give the casserole a few minutes before deciding whether it needs thickening. If the sauce is still thinner than you would like, mix 1 tablespoon of cornflour with 1-2 tablespoons of cold water until completely smooth. Stir this slurry into the casserole and cook on HIGH for another 15-20 minutes.
You can also remove the lid for the final part of cooking to allow some moisture to escape.
Serving Suggestions
Because this chicken casserole already contains potatoes and plenty of vegetables, most of the time I serve it exactly as it is. On really busy evenings, a big bowl of casserole and some bread for dipping is more than enough.
For an extra cosy dinner, leave the potatoes out of the slow cooker and serve the casserole over my creamy mashed potatoes.
Something green on the side balances the creamy casserole really well. My garlic spring greens take less than 10 minutes, while roasted tenderstem broccoli would add a little crispness.
For dipping into all that sauce, try my slow cooker bread or some easy cheesy garlic bread.
Storage
Store: Let leftovers cool and transfer them to an airtight container. Keep in the fridge for up to 3 days.
Freeze: Freeze cooled portions for up to 3 months. The potatoes can become slightly softer or grainier after freezing. It doesn't bother me, but if you are making this specifically for the freezer you could leave the potatoes out and serve freshly cooked potatoes alongside it later.
Defrost: Defrost thoroughly in the fridge overnight.
Reheat: Reheat gently on the hob or in the microwave until piping hot all the way through. Stir during reheating so the chicken and sauce heat evenly.
Troubleshooting Guide
| Problem | Likely cause | Fix |
|---|---|---|
| Casserole is watery | Too much liquid added | Use only 200ml stock and thicken at the end with a cornflour slurry if necessary |
| Potatoes are still firm | Pieces too large or sitting above the liquid | Halve new potatoes and put them towards the bottom of the slow cooker |
| Chicken is dry | Breast meat or excessive cooking time | Use thighs for the juiciest result and stick to the tested cooking time |
| Sauce looks split | Dairy cooked for too long | Add the crème fraîche only at the end |
| Casserole tastes bland | Stock or seasoning too mild | Use a good-quality chicken stock and season again before serving |
Dannii's Top Tips
- Keep the vegetables fairly chunky so they hold their shape during slow cooking.
- Leave the skins on clean baby potatoes when you need to save a few minutes of prep.
- Halve larger mushrooms rather than slicing them thinly so they don't disappear into the sauce.
- Don't add extra stock at the beginning - the chicken, mushrooms and vegetables release plenty of liquid.
- Stir the crème fraîche in only once the casserole has finished cooking.
- Taste at the end and adjust the salt and pepper; a well-seasoned stock makes a big difference.
- Finish with fresh parsley just before serving to brighten up the creamy sauce.
Frequently Asked Questions
No. This recipe has been designed as a no-browning slow cooker chicken casserole, so the raw chicken thighs can go straight into the slow cooker.
Browning chicken first can create extra savoury flavour and colour, but it isn't essential here. For me, the benefit of being able to get everything into the slow cooker quickly outweighs washing another frying pan on a busy day.
Cook this chicken casserole for 4 hours on HIGH or 6-7 hours on LOW, until the chicken is cooked through and the vegetables are tender.
Yes, although chicken thighs are my preferred option because they stay juicier during slow cooking. Chicken breast can become dry if cooked for too long, so check it earlier.
Yes, although you will lose the creamy finish. Thick double cream can be used instead. If you leave the dairy out completely, you may want to thicken the cooking liquid separately before serving.
If the sauce is too thin after the crème fraîche has been added, mix 1 tablespoon of cornflour with 1-2 tablespoons of cold water. Stir it into the casserole and cook on HIGH for another 15-20 minutes.
Each serving contains approximately 362 calories, 35g of protein and 5g of fibre, with plenty of vegetables including carrots, celery, leek and mushrooms. Whether it fits your individual diet will depend on your own nutritional needs, but it makes a filling, balanced family meal.
Yes. Once completely cool, portion it into freezer-safe containers and freeze for up to 3 months. Defrost overnight in the fridge before reheating thoroughly.
More Slow Cooker Chicken Recipes
If you've tried this slow cooked chicken casserole recipe, let us know how you got on in the comments below.
Tag us in your creations on Instagram @hungryhealthyhappy and use the hashtag #hungryhealthyhappy too.
Recipe
Slow Cooker Chicken Casserole
Recipe Video
Ingredients
- 5 Shallots - halved
- 1 Leek - sliced
- 100 g (1 cup) of Button mushrooms - halved
- 2 rib of Celery - sliced
- 2 Carrot - peeled and chopped
- 270 g (9 ½ oz) of New potatoes - halved
- 600 g (1 ⅓ lb) of Chicken thighs - skinless and boneless
- 2 Garlic cloves - crushed
- 200 ml (¾ cup) of Chicken stock
- 1 teaspoon of Thyme
- 1 teaspoon of Dried oregano
- 2 tablespoons of Wholegrain mustard
- ¼ teaspoon of Fine sea salt
- ½ teaspoon of Ground black pepper
- 100 ml (½ cup) of Crème fraîche
- 10 g (⅔ cup) of Fresh parsley - finely chopped
Instructions
- Add the vegetables: Put 5 Shallots (halved), 1 Leek (sliced), 100 g of Button mushrooms (halved), 2 Carrot (chopped), 2 rib of Celery (sliced) and 270 g of New potatoes (halved) into the slow cooker.
- Keep the carrots and potatoes towards the bottom, where they will be closest to the heat and cooking liquid.
- Add the chicken: Place 600 g of Chicken thighs on top of the vegetables.
- Add the liquid: Mix together 200 ml of Chicken stock, 2 Garlic cloves (crushed), 2 tablespoons of Wholegrain mustard, 1 teaspoon of Thyme, 1 teaspoon of Dried oregano, ¼ teaspoon of Fine sea salt and ½ teaspoon of Ground black pepper. Pour it over the chicken and vegetables.
- Cook: Put the lid on and cook on HIGH for 4 hours or LOW for 6-7 hours, until the vegetables are tender and the chicken is cooked through.
- Pull the chicken: Remove or gently pull apart the chicken and shred it into large chunks. I prefer keeping some bigger pieces rather than shredding it very finely.
- Add the crème fraîche and parsley: Add 100 ml of Crème fraîche and 10 g of Fresh parsley (chopped).
- Check and serve: Carefully stir everything together. Taste and adjust the seasoning before serving.
Recipe Notes
- Keep the vegetables fairly chunky so they hold their shape during slow cooking.
- Leave the skins on clean baby potatoes when you need to save a few minutes of prep.
- Halve larger mushrooms rather than slicing them thinly so they don't disappear into the sauce.
- Don't add extra stock at the beginning - the chicken, mushrooms and vegetables release plenty of liquid.
- Stir the crème fraîche in only once the casserole has finished cooking.
- Taste at the end and adjust the salt and pepper; a well-seasoned stock makes a big difference.
- Finish with fresh parsley just before serving to brighten up the creamy sauce.
Nutritional Information
Where nutritional information is provided, it is approximate and calculated using online tools. Values can vary depending on the ingredients and brands used, but we endeavour to be as accurate as possible.
All timings are a guide and may vary depending on the ingredients, equipment and, where relevant, the appliance used. Changing the serving size may also affect the time needed.
Jess says
I love easy this is! Perfect for busy nights shuttling the kids around!
Sue L says
We love anything chicken in this house, and I love anytime I can use the slow cooker. win-win!
Danielle Wolter says
Now this is like the perfect comfort food. Loving how easy it is, and the flavor is so yummy!
Alisha Rodrigues says
Slow cooker recipes always have so much flavor in there. I love how you've used basic ingredients to bring this recipe together. Love it !!
Mahy says
I love how crisp and clear your photos are! And the dish is just perfect for this time of the year. Yum, too!
Christian Guzman says
This looks incredible! I love that you've used the chicken thighs which I think are really the most flavorful than the others. This will be a great recipe to pop in the crock pot before I go out with my grandfather to get some firewood next weekend.
Jessica Formicola says
I'm always looking to step up my chicken dinner game, and this looks like the perfect recipe to do so! Thanks for sharing!
Jessica Formicola says
I'm always looking for new ways to make chicken for dinner, and this casserole looks like just the recipe!
Emily Liao says
This chicken casserole was amazing! Loved how it can be made right in the slow cooker :)
Gloria says
I love slow cooker meals. Especially during comfort food season. I know this would be a great dinner that the family would devour.
Bintu | Recipes From A Pantry says
You just can't beat comfort food like this. I use my slow cooker a lot in the colder months so will definitely be trying this delicious casserole.
Chichi says
I love slow cooker recipes because of the convenience of cooking. I need to use my slow cooker more. This is the perfect season too. Thank you for this yummy recipe.
Jacqueline Meldrum says
I love a casserole at this time of year and anything with mushrooms in has my name on it.
Gina says
Such a delicious combination of flavors - especially love the shallots and mushrooms in this dish. A great one everyone loves in our house!
Emmeline says
Mm this is my type of fall comfort food!! Love that you added mustard - what a nice kick!