01 - Preheat oven to 375°F. Lightly grease a standard 6-cup muffin tin or line with muffin liners.
02 - In a large mixing bowl, combine ground turkey, onion, carrot, celery, and garlic. Add breadcrumbs, egg, milk, parsley, thyme, salt, pepper, and Worcestershire sauce. Mix gently until just combined—do not overwork the meat.
03 - Divide the mixture evenly among the muffin cups, pressing lightly to fill each cup.
04 - In a small bowl, mix together ketchup, brown sugar, and Dijon mustard. Brush the glaze generously over the tops of each meatloaf muffin.
05 - Bake for 25 minutes, or until the muffins are cooked through and the tops are caramelized. Internal temperature should reach at least 165°F.
06 - Allow to rest 5 minutes before removing from the tin. Serve warm.