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 the ground turkey, onion, carrot, celery, and garlic. Add breadcrumbs, egg, milk, parsley, thyme, salt, pepper, and Worcestershire sauce. Mix gently until just combined, being careful not to overwork the meat.
03 - Divide the mixture evenly among the muffin cups, pressing lightly to fill each cup.
04 - In a small bowl, whisk together ketchup, brown sugar, and Dijon mustard. Brush the glaze generously over the top of each meatloaf muffin.
05 - Bake for 25 minutes, or until the muffins are cooked through and the tops are caramelized. The internal temperature should reach at least 165°F.
06 - Allow the muffins to rest for 5 minutes before removing from the tin. Serve warm.