01 - Set the oven to 375°F and allow it to reach temperature.
02 - Arrange the bell pepper halves cut-side up in a baking dish and roast for 10 minutes to begin softening.
03 - Heat olive oil in a large skillet over medium-high heat. Add onions and mushrooms, sautéing until softened, about 5 minutes.
04 - Incorporate minced garlic and cook for 1 minute until fragrant.
05 - Add thinly sliced beef to the skillet. Season with salt, pepper, and Worcestershire sauce. Stir and cook until beef is just done, approximately 3 to 4 minutes.
06 - If using, stir in softened cream cheese until melted and uniformly mixed. Remove from heat.
07 - Retrieve peppers from oven and spoon beef mixture evenly into each pepper half.
08 - Place one slice of provolone cheese on top of each stuffed pepper.
09 - Return peppers to the oven and bake for 15 to 20 minutes until cheese melts and peppers are tender.
10 - Present immediately while hot for optimal enjoyment.