Preheat your oven to 375°F (190°C).

Heat a tablespoon of olive oil in a large skillet over medium heat. Add diced green bell pepper and onion, and sauté for about 5 minutes until tender.

In a large mixing bowl, combine ground beef, breadcrumbs, egg, milk, Worcestershire sauce, garlic powder, salt, and pepper. Mix gently until combined.

Press half of the meat mixture into the bottom of a loaf pan to form an even layer.

Place 4 slices of provolone cheese on top of the meat layer, followed by the sautéed onions and peppers.

Spread the remaining meat mixture over the veggies and cheese, sealing the edges.

Bake in the preheated oven for 45-50 minutes, until firm and golden brown, reaching an internal temperature of 160°F (71°C). Add remaining cheese for the last 5 minutes of baking.

Let the meatloaf rest for 5-10 minutes before slicing. Garnish with fresh parsley, if desired.