In a large bowl, combine ground meat, beef broth, breadcrumbs, riced veggie medley, milk, garlic, egg, sun-dried tomatoes, Worcestershire sauce, Dijon mustard, thyme, mustard powder, salt, and pepper. Mix until fully combined. Fold in caramelized onions and ½ Cup of Gruyère Cheese, form meatloaf in pan.
Bake for 1 hour, remove from oven, drizzle with remaining Gruyère Cheese, place back in oven for additional 5 minutes, until cheese is melted.
Remove from oven add Caramelized Cipolline Onions and sun-dried tomatoes on top and ready to serve.