Preheat your oven to 375°F (190°C). Gather your ingredients and equipment.

In a skillet over medium heat, add olive oil and sauté diced green bell pepper and onion for 5 minutes until softened.

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

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

Layer 4 slices of provolone cheese over the meat, then add the sautéed bell peppers and onions on top.

Seal with the remaining meat mixture, pressing gently at the edges.

Bake in the preheated oven for 45-50 minutes until the internal temperature reaches 160°F (70°C).

In the last 5 minutes of baking, add 4 more slices of provolone cheese on top.

Once baked, remove from oven and let rest for 5-10 minutes before slicing.