Preheat oven to 350°F (175°C) and grease or line a loaf pan
Heat olive oil in a skillet over medium heat, sauté bell pepper, onion, and mushrooms until soft, about 5-7 minutes, then add garlic for 1 more minute and let cool
In a large bowl, combine ground beef, cooled vegetables, provolone and mozzarella, breadcrumbs, eggs, milk, Worcestershire sauce, ketchup, salt, pepper, oregano, and thyme; mix well
Press the mixture into the prepared loaf pan
Bake for 45 minutes
Sprinkle remaining provolone and mozzarella on top and bake an additional 10-15 minutes until cheese is melted and meatloaf reaches 160°F (71°C)
Let rest 10 minutes before slicing and serve hot
Prep Time: 20 minutes
Cook Time: 60 minutes
Total Time: 1 hour 20 minutes
Servings: 6
