Add the chopped carrot and chopped swede to a pan.
Cover with boiled water. Bring back to the boil and then simmer for 20 minutes.
Drain and return to the pan. Mash to your desired consistency.
Add the butter, salt and pepper. Stir well until the butter has melted.
Notes
Feel free to use a mixture of vegetables, and you could even add some broccoli and cauliflower too.
You don't have to make this mash creamy, but a little bit of milk and some cream cheese make it extra creamy and comforting.
If you are going to freeze the mash, make sure it has plenty of fat added to it otherwise it won't freeze successfully.
Make sure you cut the carrot and swede to similar sizes so they all cook at the same rate. You don't want any undercooked chunks, as they will not mash well.
If you want a smoother carrot and swede mash, more like a puree, then put it in a food processor and pulse it until it is the consistency that you want. We like it with some chunks in it. Swede is harder than potato, so you will never get a smooth mash like with potato.
You could roast the carrots and swede instead of boiling them, which would intensify the flavour.