Preheat your oven to 375°F (190°C).

In a small bowl, mix the softened butter, minced garlic, dried parsley, and salt until well combined.

Slice the French bread loaves in half lengthwise and spread the garlic butter mixture evenly on each half. Place the bread on a baking sheet, cut side up.

In a large skillet over medium heat, cook the ground beef and diced onion until the beef is browned and the onion is translucent, about 5-7 minutes. Drain excess fat.

Stir in the ketchup, mustard, Worcestershire sauce, and brown sugar. Simmer for about 5 minutes until heated through.

Spoon the sloppy joe mixture evenly over the garlic buttered bread halves.

Sprinkle the shredded cheddar and mozzarella cheeses generously over the sloppy joe mixture.

Bake in the preheated oven for 15-20 minutes, or until the cheese is melted and bubbly.

Remove from the oven and let cool for a few minutes before slicing into pieces.