01 - Set oven to 400°F and line a baking sheet with parchment paper.
02 - In a large skillet over medium heat, cook ground beef until thoroughly browned, breaking it up during cooking. Drain any excess fat if necessary.
03 - Add chopped onion, bell pepper, and minced garlic to the skillet. Cook for 3–4 minutes until vegetables have softened.
04 - Stir in tomato sauce, tomato paste, ketchup, Worcestershire sauce, smoked paprika, brown sugar, salt, black pepper, and oregano. Simmer for 8–10 minutes, stirring occasionally, until the mixture thickens. Remove from heat.
05 - In a mixing bowl, combine softened butter, minced garlic, chopped parsley, and 1/4 teaspoon salt until evenly blended.
06 - Slice the baguette in half lengthwise. Spread the garlic butter mixture evenly on both cut sides. Place bread halves cut side up on the prepared baking sheet.
07 - Bake bread in the preheated oven for 5–6 minutes until lightly golden. Remove from oven.
08 - Spoon the sloppy joe filling generously onto one half of each bread piece. Top with shredded mozzarella and grated Parmesan cheese.
09 - Return the filled bread halves to the oven and bake for 5–6 minutes, until the cheese is melted and bubbly.
10 - Sandwich the bread halves together, press gently, and slice into portions with a sharp knife. Serve while hot.