01 - Set oven to 400°F. Line a baking sheet with parchment paper.
02 - Add ground beef to a large skillet over medium heat. Cook while breaking up the meat with a spoon until browned throughout. Drain excess fat if necessary.
03 - Add finely chopped onion, green bell pepper, and minced garlic to the beef. Sauté for 3 to 4 minutes until the vegetables have softened.
04 - Stir in tomato sauce, tomato paste, ketchup, Worcestershire sauce, smoked paprika, brown sugar, salt, black pepper, and dried oregano. Bring to a simmer and cook for 8 to 10 minutes until thickened. Remove from heat.
05 - Slice the baguette or loaf in half lengthwise. In a small bowl, blend softened butter, minced garlic, chopped parsley, and 1/4 teaspoon salt until evenly combined.
06 - Spread garlic butter mixture over the cut sides of each bread half. Arrange bread, cut side up, on the prepared baking sheet.
07 - Bake in the oven for 5 to 6 minutes, or until the surface is lightly golden. Remove from the oven.
08 - Portion the sloppy joe mixture generously onto one half of each bread piece. Sprinkle mozzarella and Parmesan cheese evenly over the filling.
09 - Return the assembled bread to the oven for 5 to 6 minutes, until cheeses are melted and bubbly.
10 - Place the remaining bread halves on top to sandwich the filling. Press gently, then slice into serving portions and serve hot.