For the sandwiches:
- 1 tablespoon butter
- 1 small onion, thinly sliced
- 1 small bell pepper, thinly sliced
- 1 tablespoon vegetable oil
- Kosher salt and freshly ground black pepper
- 1 1/4 pounds ribeye, beef round, or top sirloin, thinly sliced
- 4 sturdy hoagie rolls
- Mayonnaise, if desired
- 8 slices mozzarella, provolone, or white American cheese
- 1/2 teaspoon dried oregano
Preheat the oven to 400°F.
In a large skillet over medium heat, melt the butter. Saute the onion and pepper until they are tender. Remove the vegetables to a bowl and heat the oil in the same pan. Add the beef and season to taste with salt and pepper. Saute until lightly browned and cooked through. Divide the meat into two batches if necessary.
Spread each bun with mayonnaise, if desired. Divide the beef and vegetable mixture among the buns. Top with the cheese and oregano. Bake the sandwiches in the oven until the cheese is melted and the bread is slightly toasted, about 5 minutes. Serve.