1. Preheat oven to 375ºF. Mist a 12-cup muffin tin with cooking spray. In a small bowl, whisk 1/2 cup ketchup with brown sugar.
2. Place beef in a bowl and break apart with your fingers. Add bread crumbs, Worcestershire, mustard, eggs, onion, parsley, salt, pepper and remaining 2/3 cup ketchup. Using your hands, mix ingredients gently but thoroughly. Divide among muffin cups. Spread 2 tsp. ketchup mixture on each.
3. Bake until an instant-read thermometer inserted in center of a loaf reads 160ºF, 25 to 30 minutes. Let cool in pan on rack for 10 minutes.
Make it ahead
TO FREEZE: Cool completely. Remove from pan. Freeze on parchment-lined baking sheet. Wrap each in foil, place in a freezer bag and return to freezer.
TO SERVE: Thaw in the fridge overnight. Unwrap; place in greased baking dish. Bake uncovered at 350ºF, 15 to 20 minutes