Do Ahead Party Potatoes - cooking recipe

Ingredients

5 lb. potatoes, boiled and mashed
1 stick butter
1/4 c. milk
8 oz. sour cream
8 oz. cream cheese
salt and pepper to taste
5 large Vidalia or any large sweet onions, peeled and sliced 1/2-inch thick
1 stick butter
1 c. chicken broth or 1 c. water and 2 chicken bouillon cubes
4 Tbsp. flour
1 1/2 c. soft bread crumbs, made in food processor
1/2 c. grated 3-year-old Cheddar cheese (from Humbird Cheese House, Tomah, Wisconsin)
4 Tbsp. grated Parmesan cheese

Preparation

Saute onions in butter until transparent. Stir in flour to make a roux. Add hot chicken broth gradually and stir for 3 minutes. When slightly thickened, transfer to casserole dish. Mix soft bread crumbs with cheeses and sprinkle on top of onions. Bake at 350\u00b0 for 45 minutes or until lightly browned and bubbly.