01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large skillet over medium heat, cook the ground beef until well browned, breaking it apart as it cooks. Drain excess fat as needed.
03 - Add chopped onion, bell pepper, and minced garlic to the skillet. Cook for 3 to 4 minutes until softened.
04 - Stir in tomato sauce, tomato paste, ketchup, Worcestershire sauce, smoked paprika, brown sugar, salt, black pepper, and dried oregano. Simmer for 8 to 10 minutes until thickened. Remove from heat.
05 - Slice baguette in half lengthwise. In a mixing bowl, combine softened butter, minced garlic, chopped parsley, and salt.
06 - Spread the garlic butter mixture evenly over both cut sides of the bread. Arrange bread halves cut side up on the prepared baking sheet.
07 - Bake in preheated oven for 5 to 6 minutes until lightly golden.
08 - Generously spoon the prepared sloppy joe filling over one half of each bread piece. Sprinkle evenly with mozzarella and Parmesan cheese.
09 - Return to oven for 5 to 6 minutes until the cheese is melted and bubbling.
10 - Close the sandwiches with the top halves, press gently, and slice into portions. Serve immediately while hot.