- 2 tablespoons extra-virgin olive oil
- 1/2 pound cremini mushrooms, sliced
- 1 large onion, quartered lengthwise then sliced
- 2 Cubanelle peppers, seeded and halved lengthwise, then thinly sliced
- Salt and freshly ground black pepper
- 1/2 cup beef stock
- 1 pound bulk hot Italian sausage
- 1 pound ground sirloin
- 1 tablespoon grill seasoning
- 2 large cloves garlic, grated
- A handful flat-leaf parsley, finely chopped
- 8 deli slices provolone cheese
- 4 sesame Kaiser rolls, split
Heat 1 tablespoon olive oil in a medium skillet over medium-high heat. Saute mushrooms, onions and peppers until tender, 7 to 8 minutes then season with salt and pepper. Deglaze the pan with stock.
Combine the sausage and sirloin with grill seasoning, garlic and parsley. Mix and form 4 patties thinner at the center and thicker at the edges for even cooking and to keep burgers from bulging. Heat cast iron or nonstick skillet with 1 tablespoon olive oil over medium-high heat, cook patties 12 minutes turning once and top with mushrooms, onions and peppers and 2 slices of cheese. Turn heat off and cover pan with foil to melt cheese, 2 minutes. Pile on buns and serve.