Prepare the chicken in advance. Season and marinate the chicken for at least 3 hours or overnight.

In a deep pot, melt the butter over a low flame and carefully place the chicken breasts.

Cover and allow to cook for about 7 minutes.

Turn on other side, cover and cook for 7 minutes.

Note: What we want to achieve is a cooked but tender chicken breast. So keep the fire low and let the chicken breasts cook slowly in their juices.

Next, remove the chicken breasts. Set aside.

In the same pot, add the chopped onion and saute until translucent.

Add the flour and mushrooms. Stir.

Then add the milk and heavy cream. simmer for 3 minutes or until thick.

Return the chicken breasts and cover with the sauce. Serve hot.