Peel potatoes and boil until fork tender. While potatoes are boiling, cook breakfast sausage in skillet, drain and set aside. Drain potatoes, add butter, milk, salt, and pepper, and beat until creamy.
Combine all ingredients in layers (in clear glass loaf pan), with potatoes last and on top i.e.: sausage, then sauerkraut with a small amount of juice, diced Velveeta Cheese chunks until your loaf pan is almost full. Spread mashed potatoes on top until fully covered and smooth, this seals the dish.
Bake on approx. (depending on oven) 375-400°F for approx 30-40 minutes, or until the mashed potatoes look crisp on top and you can see the cheese melted and the juice bubbling. Remove from oven and place more Velveeta cheese on top to melt. Let stand for approx. 15 minutes to set up and cool.