Place steak in freezer until firm, about 45 minutes. Using a sharp knife, slice steak against the grain as thinly as possible, and refrigerate slices until ready for use.

Heat oven to 400°F. In a large skillet or sauté pan, heat 2 tablespoons oil over medium heat before adding onion and bell pepper (if desired). Season with salt and pepper, and cook until tender, about 8 minutes. Remove from pan and set aside.

Place rolls on a baking sheet, and set in oven until warm but not crisp, about 5 minutes.

While rolls are warming, heat 1 tablespoon of oil in the sauté pan over medium heat, and add a third of the sliced meat. Season with salt and pepper, and cook until meat is no longer pink, about 3 minutes. Add a third of the sautéed vegetables to the pan, and mix with sliced meat.

Divide the mixture into two piles, and top each with 2 ounces of provolone. Cover pan, and let cook undisturbed until cheese is melted and vegetables are warmed through, about 3 minutes. Scoop each pile onto a warmed roll, and repeat process for other 4 sandwiches.