In large bowl mix soup, sour cream,french onion dip, cheese,peppers, onions and mushrooms. Mix well When all ingredients are thoroughly mixed fold in package of hash browns.
Spray a 9x12 baking dish and pour in half of the hash brown mixture. Spread half of the sausage over this layer.Spread remaining hash brown mixture over sausage. Spread remaining sausage over top.
Bake in 350 degree over for about an hour or until casserole is thoroughly hot and bubbly. Remove from oven and allow to sit for 10 to 15 minutes before serving to allow casserole to set up making it easier to serve.