Preheat oven to 350°F and grease a 9×13” baking dish.
Layer boiled potatoes and browned sausage evenly in dish.
In saucepan, melt butter, Velveeta, and milk until smooth.
Add cream cheese, paprika, salt and pepper; stir well.
Pour cheese sauce over sausage and potatoes.
Top with shredded cheddar and optional mozzarella.
Bake uncovered for 25–30 minutes until bubbly and golden.
