Preheat your oven to 350°F (175°C). In a large skillet or Dutch oven, melt 2 tablespoons of olive oil or butter over medium heat. Add the thinly sliced yellow onion and green bell pepper. Sauté gently, stirring occasionally, for 8 to 10 minutes until the onions are softened and just beginning to caramelize. Stir in the minced garlic for the last minute until fragrant.

Add the ground beef to the skillet with the vegetables. Break the beef up with a wooden spoon and cook until it is fully browned with no pink bits remaining. Drain off any excess grease. Season the beef mixture generously with salt, pepper, garlic powder, onion powder, and Worcestershire sauce (if using). Stir well to combine. Reduce heat to low and set aside.

Carefully slice the whole block of Hawaiian sweet rolls horizontally, keeping the top and bottom connected. Place the bottom half of the rolls into a 9x13 inch baking dish.

Arrange half of the provolone cheese slices directly over the bottom layer of the bread.

Evenly spoon the seasoned ground beef, onion, and pepper mixture over the layer of cheese. Spread it to cover the entire surface.

Place the remaining slices of provolone cheese over the beef filling. Gently place the top half of the rolls back over the cheese and filling.

In a small, microwave-safe bowl, melt the 4 tablespoons of butter. Stir in the garlic salt and dried parsley or Italian seasoning. Brush the entire mixture over the tops of the sweet rolls, ensuring it drips into the sides. Cover the baking dish tightly with aluminum foil and bake for 15 minutes, then remove the foil and bake for an additional 5 minutes until the tops are golden brown and the cheese is melted. Let cool for 5 minutes before serving.