Preheat oven to 350°F. Prepare macaroni according to package directions.
Gently stir together macaroni, Cheddar cheese, cottage cheese, sour cream, ham, onion, salt, pepper, and egg in a large bowl. Transfer to a 2-quart baking dish coated with cooking spray.
Stir together breadcrumbs, butter, and paprika in a small bowl. Sprinkle breadcrumb mixture diagonally across the top of the macaroni mixture, forming stripes.
Bake in preheated oven until golden brown, 30 to 35 minutes. Top with sliced tomatoes and parsley, if desired.
Recipe Revival, Oxmoor House, copyright 2016.