• Gather all your ingredients so that you have everything close at hand on the counter or table.

Prepare the Ingredients

• Using a cutting board and a Santoku knife, slice the 1 1/2 pounds "untenderized" round steak into thin strips.
• With a Chef's knife on a second cutting board, slice 1 large sweet onion, 1 large green bell pepper, and 4 medium button mushrooms. Mince 1 clove garlic.
• Using a box grater, shred 1 cup mozzarella cheese and 1 cup provolone cheese. Set aside until ready to use.

Make the Steak Sandwich

• In a large skillet, sauté the sliced sweet onion, green bell pepper, mushrooms, and minced garlic in 2 tablespoons olive oil until tender and onions have caramelized. Season with 1 teaspoon kosher saltand 1 teaspoon freshly ground black pepper. Remove from pan and keep warm in a bowl.
• With the same skillet, and using more olive oil, if needed, cook the prepared strips of steak on medium-high heat until brown. Sprinkle with more kosher salt and freshly ground black pepper.
• Remove from heat. Cover the steak with the grated cheese and allow it to melt.
• Toast 1 package hoagie rolls in the oven or in a toaster oven until lightly browned. Another option is to butter the inside of the rolls and heat on a griddle until nicely browned.
• To make the sandwiches, pile spoonfuls of cheesy meat on toasted rolls, then top with generous amounts of the onion mixture. Makes 4-6 sandwiches.