For a richer flavor, use full-fat sour cream and cottage cheese. Feel free to add other cheeses, such as Gruyere or cheddar, for a more complex flavor profile. A sprinkle of paprika over the top before baking adds a touch of color and smoky flavor. This casserole can be assembled ahead of time and refrigerated until ready to bake. Add about 10 minutes to the baking time if baking from cold. Try adding cooked ham or bacon to the casserole for a heartier meal.