Preheat the Oven: Preheat your oven to 375°F (190°C).
Cook the Meat: In a large skillet over medium heat, cook the ground beef until browned. Drain any excess fat.
Add Veggies: Add the chopped onion and green bell pepper to the skillet. Cook until softened, about 5 minutes.
Mix the Sauce: Stir in the tomato sauce, ketchup, brown sugar, Worcestershire sauce, garlic powder, salt, and black pepper. Let the mixture simmer for 10 minutes, stirring occasionally.
Prepare the Bread: Place the French bread halves on a baking sheet. In a small bowl, combine the melted butter and minced garlic. Brush the garlic butter over the cut sides of the bread.
Add the Meat Mixture: Spoon the sloppy joe mixture evenly over the garlic bread halves.
Top with Cheese: Sprinkle the shredded mozzarella cheese evenly over the top of the meat mixture.
Bake: Bake in the preheated oven for 10-12 minutes, or until the cheese is melted and bubbly.
Garnish and Serve: Remove from the oven, garnish with chopped parsley if desired, and slice into pieces. Serve hot.