In a large mixing bowl slice up the sausage, peel and slice potatoes, chopped green pepper and chopped onion. Toss to mix
Spray a 9 x 13 baking dish with cooking spray and pour in the potato sausage mixture. Sprinkle cubed cheese on top.
In a saucepan on top of the stove combine the milk, sour cream, butter, salt, pepper, garlic powder and flour. Over low heat melt the ingredients while stirring with a wire whisk until mixture thickens and is smooth. DO NOT BOIL.
Remove from stove and pour over potatoes and sausage. Sprinkle shredded cheddar cheese over top. Sprinkle paprika over cheese. Cover with foil and bake in preheated 375 degree oven 35 to 40 minutes or until potatoes are tender when stuck with a fork. Remove foil and bake for 15 more minutes until starts to brown on top. Remove from oven and garnish with fresh parsley.