These Blueberry Oat Bars are a nutritious and fibre packed no-bake snack made with a homemade blueberry chia jam and a peanut butter oat crumble. They are naturally sweetened with maple syrup, packed with oats, seeds and fruit, and they make a great make-ahead breakfast, snack or healthier dessert.
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These blueberry oat bars are inspired by a dessert I used to buy from a vegetarian café when I was in university. The base and crumble topping are made from the same simple oat mixture, which keeps the recipe really easy. You just press most of it into a lined tin, spread over the thick blueberry jam, crumble the rest on top and chill until firm enough to slice.
They are easy to make with simple store cupboard ingredients and frozen or fresh blueberries. They are a great option if you want something sweet, but still filling enough to keep you going - I love one of these pre-workout.
Slightly chewy, fruity, lightly nutty and easy to adapt with different berries, seeds or nut butters. Such a versatile recipe.
They are also naturally high in fibre from the oats, chia seeds, blueberries and mixed seeds, and the peanut butter helps to make them more filling too. Because they are chilled rather than baked, they have a soft, chewy texture rather than a crunchy flapjack texture.
Looking for some more healthy snack recipes? Why not try our simple 4 Ingredient Oat Bars, our amazing Dark Chocolate Chip Energy Balls, chewy Healthy Cookies or our delicious Carrot Cake Oat Bars?
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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.
- Blueberries - Fresh or frozen blueberries both work well. Frozen blueberries may release a little more liquid, so the jam might need an extra few minutes on the hob to thicken.
- Lemon - This brightens the blueberry flavour and stops the bars from tasting too sweet. Orange zest would also work if you want a softer citrus flavour.
- Seeds - Chia seeds for the jam; flaxseeds and sunflower seeds for the bars.
- Maple syrup - Maple syrup sweetens both the jam and the oat mixture. You could use honey instead, but the flavour will be slightly different and the bars would no longer be vegan.
- Oats - Rolled oats give the bars their chewy texture. Avoid jumbo oats on their own, as they can make the bars more crumbly. If using jumbo oats, pulse some of them in a food processor first. Oat flour helps bind the mixture and gives the base a firmer texture. You can buy oat flour or make your own by blending oats until fine.
- Coconut oil - Melted coconut oil helps the bars firm up once chilled.
- Vanilla - Make sure you use extract and not essence.
- Peanut butter - This helps bind the oat mixture and gives the bars a lovely nutty flavour. Smooth, runny peanut butter works best. Almond butter or cashew butter can also be used.
Variations
Mixed berries - Use a mix of blueberries, raspberries and blackberries for a sharper, more colourful jam. Raspberries are naturally softer, so the jam may thicken a little faster.
Apple Cinnamon - Use stewed apple instead of blueberry jam and add extra cinnamon to the oat mixture. This gives the bars more of an apple crumble flavour.
Chocolate - Stir a few dark chocolate chips into the oat mixture or drizzle melted dark chocolate over the chilled bars before slicing.
High Protein - Add a scoop of vanilla protein powder to the oat mixture. If adding protein powder, you may need to add a little extra peanut butter or maple syrup so the mixture still binds.
Nut free - Use sunflower seed butter instead of peanut butter. This is a good option for nut-free lunchboxes, but always check school rules and ingredient labels.
How To Make Blueberry Oat Bars
Make the Jam
- Step 1: Put the blueberries, water, lemon juice and zest, chia seeds and maple syrup into a saucepan.
- Step 2: Bring to the boil then simmer for 5 minutes, mashing down the blueberries.
Continue stirring while heating. - Step 3: Once cooked, allow to cool to thicken.
Make the Oat Bars
- Step 1: In a large mixing bowl, add the oats, oat flour, seeds, cinnamon, melted coconut oil, vanilla and peanut butter.
- Step 2: Mix everything together until well combined.
- Step 3: Tightly press ⅔ of the oat mixture into a lined tin. We used a 19x13cm (7.5x5 inch) tin.
A smaller tin will result in thicker bars, a larger tin will result in thinner.
- Step 4: Spread the cooled blueberry mixture over the oat mixture.
- Step 5: Crumble the remaining oat mixture over the jam layer.
- Step 6: Carefully spread the crumbled oats mixture over the jam.
- Step 7: Refrigerate for 5 hours. Once chilled, cut into bars.
How To Stop Them Being Crumbly
These are naturally a little bit crumbly, but they shouldn't fall apart. The most common reason these bars turn out crumbly is that the oat mixture is too dry or has not been pressed firmly enough into the tin.
The mixture should hold together when you squeeze a small handful. If it falls apart straight away, add a little more peanut butter, maple syrup or melted coconut oil. Add it gradually, as too much liquid can make the bars greasy or too soft.
Make sure the base is pressed down really tightly. Use the back of a spoon, a spatula or the bottom of a glass to compact it into the tin. Don't just lightly spread it in, as this will make the bars fall apart when sliced.
The jam should also be thick and cooled before adding it to the base. If the jam is too runny, it can make the middle too soft and stop the bars from setting properly.
Chilling time matters too. These bars need at least 5 hours in the fridge, but overnight is even better. If you slice them too soon, they will be much more likely to crumble.
For neater slices, use a sharp knife and wipe it between cuts. You can also chill the bars in the freezer for 20-30 minutes before slicing if they still feel too soft.
Blueberry Oat Bar Storage
Store the blueberry oat bars in an airtight container in the fridge for up to 5 days. They are best kept chilled, as the coconut oil and peanut butter help them stay firm.
You can layer them between pieces of baking paper to stop them sticking together. They are fine to eat straight from the refrigerator, but you can leave them at room temperature for 5-10 minutes if you prefer a softer texture.
These bars also freeze well. Freeze them in a single layer first, then transfer to a freezer-safe container or bag. They will keep well for up to 3 months. Defrost in the fridge overnight or leave one at room temperature for a short time before eating.
If freezing for lunchboxes (remember to make nut free), put a frozen bar straight into the lunchbox in the morning and it should be defrosted by snack time, depending on room temperature.
Dannii's Top Tips
- Let the blueberry jam cool before spreading it over the oat base. Warm jam can soften the base and make the bars harder to set.
- Don't make the jam too runny. It should be thick enough to spread, not pour like a sauce. If it looks watery, keep cooking it for a few more minutes.
- Use baking paper with overhang so you can lift the whole slab out of the tin before slicing.
- For thicker bars, use a smaller tin. Thinner bars will set faster, but they can be more delicate.
- Press the crumble topping down lightly so it sticks to the jam layer. You still want it to look crumbly, but it needs a little pressure to stop it falling off.
- If the mixture feels too oily, add a little more oat flour. If it feels too dry, add a little more peanut butter or maple syrup.
- For a smoother texture, blend more of the oats before mixing. A combination of whole oats and finer oats helps the bars hold together better.
- Always chill before slicing. These bars are not designed to be cut straight away, as they need time to firm up.
- Use certified gluten-free oats to ensure this recipe is gluten free.
More Snack Bar Recipes
If you've tried these healthy blueberry oatmeal bars, let us know how you got on in the comments below.
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Recipe
Blueberry Oat Bars
Recipe Video
Ingredients
Blueberry Jam:
- 225 g (1.5 cups) of Frozen blueberries
- 1 tablespoon of Water
- 1 tablespoon of Lemon juice
- 1 teaspoon of Lemon zest
- 1.5 tablespoons of Chia seeds
- 1 tablespoon of Maple syrup
Oat Bars:
- 110 g (1 cups) of Oats - blended into flour
- 80 g (0.75 cup) of Oats - left whole
(use certified gluten free oats to ensure this recipe is gluten free)
- 1 tablespoon of Ground flaxseeds
- 1 tablespoon of Sunflower seeds
- 0.5 teaspoon of Ground cinnamon
- 2 tablespoons of Coconut oil - melted
- 130 g (0.5 cup) of Peanut butter
- 1 teaspoon of Vanilla extract
Instructions
For the Jam
- Put 225 g of Frozen blueberries, 1 tbsp of Water, 1 tbsp of Lemon juice, 1 tsp of Lemon zest, 1.5 tablespoons of Chia seeds and 1 tbsp of Maple syrup into a saucepan.
- Bring to the boil then simmer for 5 minutes, mashing down the blueberries.Continue stirring while heating.
- Once cooked, allow to cool to thicken.
For the Oat Bars
- In a large mixing bowl, add 80 g of Oats (whole), 110 g of Oats (flour), 1 tbsp of Ground flaxseeds, 1 tbsp of Sunflower seeds, 0.5 tsp of Ground cinnamon, 2 tablespoons of Coconut oil (melted), 1 tsp of Vanilla extract and 130 g of Peanut butter.
- Mix everything together until well combined.
- Tightly press ⅔ of the oat mixture into a lined tin.
- Spread the cooled jam over the oat mixture.
- Crumble the remaining oat mixture over the jam layer.
- Carefully spread the crumbled oats mixture over the jam.
- Refrigerate for 5 hours. Once chilled, cut into bars.
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.
Lisa MW says
Fantastic recipe. My kids loved it & they are quite picky. I've made it twice. Love all of the recipes on here.