Put chicken, water, and bouillon cubes in crockpot and cook on high for 4 hours or low for 8

After chicken is cooked, saute onions and mushrooms in pan with a 2 tablespoons additional butter

Once onions and mushrooms are sauteed, add 4 tablespoons of butter and 4 tablespoons of flour. Mix vigorously so you don't have lumpy gravy.

Let flour cook for about a minute stirring constantly. Add 3 cups of crockpot juice and stir well. Add salt and pepper to taste.

Shred chicken and add to gravy. Let chicken heat through.

Pour over mashed potatoes and enjoy