Mushroom sauce

Place the butter in a frying pan and place over medium heat.

Add all the chopped onions, mix well and leave for 10 minutes until the onions turn a little translucent golden.

Add finely chopped champignons, mix well and add salt. Close the lid for 5 minutes.

Add a tablespoon of flour, stir.

After 3 minutes, add a glass of cream (or milk), mix well and close the lid for 10 minutes.

Add salt, pepper and mix.