Preheat the oven to 400˚F. In a small bowl mix together the breadcrumbs and milk and set aside.
Heat the olive oil in a skillet set over medium heat and saute the onion, carrots, garlic and zucchini until soft but not browned, about 4 minutes. Remove from the stovetop and allow to cool.
In a large mixing bowl combine the ground beef, salt, egg, Dijon mustard and Worcestershire sauce. Add the breadcrumb mixture and veggies, and mix well.
Divide the beef into 12 equal portions shaping each into a large ball; press into the muffin tin. In a small bowl whisk together the glaze ingredients and brush over the meatloaves.
Bake for 15–18 minutes or until cooked through and the glaze is thick and sticky. Allow to cool 5 minutes before removing from muffin tin.