Note: Premium shaved beef is the key to this sandwich. The meat may be sold frozen, but make sure it's thawed when preparing the recipe.
1. Heat a large nonstick skillet over medium high heat. When it's hot, add 2 tsp. of the oil. Add onions, green pepper, and, if desired, mushrooms. Cook, watching the heat level, until vegetables have softened, darkened, and become slightly crispy, about 15 to 20 minutes. If they start to burn, lower heat. If pan gets too dry, add water. Transfer vegetables to a plate or bowl and tent with foil to keep warm.
2. Add remaining 1 tsp. oil to skillet. Increase heat to high. When it's smoking, add beef and black pepper. Break up meat with tongs and press down on meat with a spatula. When it's browned, about 2 minutes, turn it over. Top with cheese. Cook until cheese is melted and meat is browned, about 1 minute.
3. Use tongs or a spatula to divide meat and cheese among four rolls. Top with vegetable mixture. Serve immediately.
Source: Hannaford fresh Magazine, July - August 2008