3 tablespoons EVOO – Extra Virgin Olive Oil, divided
2 tablespoons butter
1 pound cremini mushrooms, chopped
Salt and pepper
1 onion chopped
2 cloves garlic, grated
12 slices Sargento Baby Swiss Slices, divided
1 1/2 pounds ground sirloin
2 tablespoons Worcestershire sauce
1 tomato, sliced
1 head green leaf lettuce
1 red onion, sliced
4 burger rolls
Heat EVOO, 2 turns of the pan, over medium-high heat with butter. When butter is melted, add mushrooms and cook to deep brown, about 10-12 minutes. Add salt, pepper, onions and garlic, stir and let soften, about 3-4 minutes more. Take pan off the heat and pour mushroom mixture into a medium-sized bowl and let cool. Chop 8 slices of Swiss cheese and mix it with the cooled mushroom mixture. Set aside.
In a medium bowl, mix ground sirloin with Worcestershire sauce, salt and pepper. Score the meat into 8 sections then roll into 8 balls and form them into very thin patties. Lay 4 of the patties on your work surface, scoop 1/4 of the mushroom cheese mixture into the center of each patty, top with another patty and pinch the sides to seal the mixture inside.
Heat a cast-iron skillet over medium-high heat with one turn of the pan of EVOO. Cook burgers in the pan, about 3-4 minutes per side. Top each burger with a slice of Swiss cheese, cover the pan with a sheet of aluminum foil to help melt the cheese then place on a burger bun. Top with a slice of tomato, some lettuce and onion, and serve.