Instructions:
1. Preheat your oven to 375°F (190°C).
2. Heat the olive oil in a skillet over medium heat. Add the diced onions, bell peppers, and minced garlic to the skillet and sauté until they are softened and lightly browned. Set aside to cool.
3. In a large mixing bowl, combine the ground beef, breadcrumbs, milk, beaten eggs, Worcestershire sauce, salt, and black pepper. Add the cooled onion and bell pepper mixture to the bowl and mix until all the ingredients are well combined.
4. Line a baking sheet or loaf pan with parchment paper or aluminum foil.
5. Transfer half of the meatloaf mixture to the lined baking sheet or loaf pan and press it down to create an even layer.
6. Layer the provolone cheese slices on top of the meat mixture, covering it completely.
7. Place the remaining meatloaf mixture on top of the cheese and press it down gently to seal the cheese in the middle.