Peel the potatoes and carrots and cut them into large pieces. Cook in salted water for 20 minutes until soft.
In the meantime, peel and dice the onion and put it in
Fry 1/2 tablespoon oil until brown. Brown the butter in a small saucepan over low heat.
Drain the vegetables, saving some of the liquid. Now mash the potatoes and carrots with a potato masher to a pulp. There should still be pieces to be seen. Add a little of the cooking liquid again. Salt well. Stir the roasted onions and brown butter into the porridge.