01 - Preheat the oven to 400°F (204°C). Line a baking sheet with parchment paper.
02 - In a large skillet over medium heat, cook the ground beef, breaking it apart, until well browned. Drain any excess fat as needed.
03 - Add the chopped onion, green bell pepper, and minced garlic to the skillet. Cook for 3 to 4 minutes until the vegetables are softened.
04 - Incorporate tomato sauce, tomato paste, ketchup, Worcestershire sauce, smoked paprika, brown sugar, salt, black pepper, and oregano. Stir well and simmer for 8 to 10 minutes until thickened. Remove from the heat.
05 - Slice the bread loaf in half lengthwise. In a small bowl, combine softened butter, minced garlic, chopped parsley, and 1/4 teaspoon salt until evenly blended.
06 - Spread garlic butter generously over both bread halves. Arrange cut side up on the lined baking sheet.
07 - Bake for 5 to 6 minutes until the bread is lightly golden. Remove from oven.
08 - Spoon the sloppy joe filling evenly onto one half of each toasted bread piece. Sprinkle with mozzarella and Parmesan cheese.
09 - Return the topped bread halves to the oven and bake for an additional 5 to 6 minutes, until the cheese melts and bubbles.
10 - Place the remaining bread halves over the filled sides to form sandwiches. Press gently and slice into portions. Serve hot.