01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large skillet over medium heat, cook ground beef, breaking it apart with a wooden spoon until well browned. Drain any excess fat.
03 - Add finely chopped yellow onion, green bell pepper, and minced garlic to the skillet. Sauté 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 the mixture for 8 to 10 minutes until thickened. Remove from heat.
05 - Slice the baguette in half lengthwise. In a small bowl, mix softened butter with finely minced garlic, chopped parsley, and 1/4 teaspoon salt until evenly combined.
06 - Evenly spread the garlic butter mixture over both bread halves. Arrange the bread on the prepared baking sheet, cut side up.
07 - Bake the bread halves for 5 to 6 minutes until lightly golden. Remove from oven.
08 - Generously spoon the beef filling onto one half of each toasted bread piece. Top with shredded mozzarella and grated Parmesan cheese.
09 - Return the assembled bread to the oven for an additional 5 to 6 minutes, until the cheese is melted and bubbly.
10 - Place the top halves of the bread over the filling, press gently, and slice into individual servings. Serve hot.