Prepare bell peppers by slicing in half (top to bottom) and remove seeds with a spoon. Lay into a 9 x 13-inch baking pan. Bake for 20 minutes.
While peppers are cooking, prepare stuffing by sauteing mushrooms and onions over medium-high heat. Add garlic and Worcestershire sauce; cook for an additional 1-2 minutes until fragrant. Stir in roast beef strips.
Remove peppers from oven and carefully stuff with roast beef and vegetable mixture. Top with sliced cheese and bake for 10-15 minutes until warmed through.
Nutrition Facts
215 calories, 9g fat, 11g carbohydrates, 20g protein