For the ultimate comfort food, our melty Provolone cheese, savory London Broil, and caramelized veggies come together in a supremely satisfying sandwich.
Add olive oil to a large skillet over medium heat. Add the sliced onions, peppers, mushrooms, salt and pepper. Stir every few minutes, until onions are caramelized and the peppers and mushrooms are softened, about 15 minutes. Set aside.
Toast the sourdough slices in a toaster until golden brown. Set aside.
Spread Boar’s Head Delicatessen Style Mustard on the sourdough toast slices. On the bottom slice, layer 1 tbsp caramelized vegetables, then 2 slices of Provolone Cheese, 6 slices London Broil Roasted Beef, and top with the remaining 2 slices of Provolone Cheese. Crown with the top slice of toast.
Place a skillet over medium heat, adding butter. Once the butter is just melted, place the sandwich into the skillet, and watch carefully for the cheese to begin melting. When the bread is golden brown on the bottom, flip the sandwich.
Continue to grill until the cheese is fully melted and the other side of bread is golden.