Preheat oven to 350°.
Heat a small skillet over medium-high heat. Coat pan with cooking spray. Add onion to pan; sauté 5 minutes or until lightly browned. Remove from heat; cool slightly.
Combine onion, breadcrumbs, and next 7 ingredients (through egg white) in a large bowl. Stir in 2 tablespoons ketchup. Spoon about 1/2 cup meat mixture into each of 3 muffin cups coated with cooking spray; place muffin tin on a baking sheet. Combine remaining 1 tablespoon ketchup and hot pepper sauce in a small bowl. Brush ketchup mixture over meat loaf tops. Bake at 350° for 30 minutes or until a thermometer registers 165°.