Preheat your oven to 350°F (175°C).

In a skillet over medium heat, add a little oil and sauté the chopped onions and green bell peppers until tender, about 5-7 minutes.

Add the minced garlic for the last minute of cooking, then remove from heat to cool.

In a large mixing bowl, combine ground beef, breadcrumbs, milk, egg, Worcestershire sauce, sautéed vegetables, salt, and pepper. Mix until just combined.

Transfer the mixture to a baking dish or loaf pan and shape it into a loaf.

Make a small indentation in the center of the loaf, fill it with half the provolone and mozzarella cheese, cover with meat mixture, then top with remaining cheese.

Place the meatloaf in the oven and bake for about 45 minutes, or until the internal temperature reaches 160°F (70°C).

Remove from the oven, let it rest for 10 minutes, then slice and serve.