01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large skillet over medium heat, cook the ground beef until browned, breaking it up as it cooks. Drain excess fat if needed.
03 - Add chopped onion, bell pepper, and minced garlic to the skillet. Cook for 3 to 4 minutes until the vegetables are softened.
04 - Stir in tomato sauce, tomato paste, ketchup, Worcestershire sauce, smoked paprika, brown sugar, salt, black pepper, and oregano. Simmer for 8 to 10 minutes until thickened, then remove from heat.
05 - Slice the baguette in half lengthwise. In a bowl, combine softened butter, minced garlic, parsley, and 1/4 teaspoon salt.
06 - Spread the garlic butter evenly over the cut side of both bread halves and place cut side up on the prepared baking sheet.
07 - Bake for 5 to 6 minutes until lightly golden. Remove from the oven.
08 - Generously spoon the sloppy joe filling onto one half of the bread. Sprinkle with mozzarella and Parmesan cheese.
09 - Return to the oven for an additional 5 to 6 minutes, until the cheese is melted and bubbly.
10 - Sandwich the bread halves together, press gently, and slice into portions. Serve hot.