Clean and wash both the carrots and potato and cut them into small pieces.
On medium heat, place a saucepan, add the water to boil.
Add the vegetables- Carrots and potato, allow to cook for about 12-15 minutes.Check with the fork if they're well cooked and if not let it cook for about 3-5 minutes more.
Take them out, allow to cool. Then mash with fork or masher, you can also use a food processor to blend everything together.
Add the melted butter and mix everything together.
At this point, breast milk can be added if you choose to.If you feel is not soft enough, more water can be added to make it softer.
Your puree is ready to be served. Do not serve too hot or too cold, let it be lukewarm .