Prepare the Meatballs: In a large mixing bowl, combine ground beef, breadcrumbs, egg, garlic powder, and seasonings. Mix until well incorporated, shape into 1 to 1.5 inch meatballs, and place on a baking sheet.

Cook the Meatballs: Heat olive oil in a skillet over medium-high heat. Add meatballs and cook for 8 to 10 minutes, turning until browned on all sides. Transfer to a plate and set aside.

Caramelize Onions: In the same skillet, add sliced onions and cook over medium-low heat for 15 to 20 minutes until caramelized. Add a pinch of sugar if desired.

Make the Sauce: Pour in the beef broth and optional wine, simmer for 5 minutes, and return the meatballs to the skillet, coating them in the onion sauce.

Add Cheese: Turn the heat to low, sprinkle grated Gruyère over the meatballs, cover with a lid, and melt cheese for about 5 minutes.

Serve: Plate the meatballs drizzled with caramelized onion sauce. Enjoy with sides like bread or mashed potatoes.