Preheat the oven to 350°F (175°C).
In a large bowl, combine ground beef, caramelized onions, breadcrumbs, milk, egg, Worcestershire sauce, garlic powder, salt, and pepper.
Mix the ingredients until well combined.
Shape the mixture into a loaf and place it in a greased baking dish.
Spread shredded Swiss cheese on top of the meatloaf.
Bake in the preheated oven for 50-60 minutes, or until the internal temperature reaches 160°F (70°C).
Let it rest for 10 minutes before slicing.
Garnish with fresh parsley before serving.
Serve with extra caramelized onions if desired.
Enjoy your delicious French onion meatloaf!