Heat olive oil in a skillet over medium heat. Add onion, garlic, and bell pepper and sauté until softened.
Stir in the ground beef and cook until browned, breaking it apart as it cooks.
Mix in tomato sauce, tomato paste, Italian seasoning, salt, and pepper. Reduce heat and simmer for 10 minutes.
Toast garlic bread slices until golden and crisp.
Spoon the beef mixture generously onto the garlic bread slices.
Top with shredded mozzarella and place under the broiler until cheese melts and bubbles.
Sprinkle with fresh parsley and serve warm, messy, and with plenty of napkins.