In a skillet over medium-high heat, cook the ground beef until browned.

Add the chopped onion and garlic, and sauté until the onion is translucent.

Season with salt and pepper to taste. Stir in Worcestershire sauce and beef broth. Let it simmer until the liquid reduces.

Butter one side of each slice of bread. Preheat a skillet or griddle over medium heat.

Place two slices of bread, butter side down, on the skillet.

Add a layer of cheddar cheese, then the beef mixture, and top with mozzarella.

Place the remaining slices of bread on top, butter side up.

Grill each side for 3–4 minutes until golden brown and the cheese has melted. Flip carefully to avoid spilling the filling.

Slice the melts and serve warm. Garnish with fresh parsley if desired.