Step 1: Prepare the Peppers : Preheat your oven to 400°F (200°C). Slice the bell peppers in half lengthwise, removing seeds and membranes. Place them cut-side up on a baking dish. Drizzle lightly with olive oil and season with a pinch of salt. Roast in the oven for 10–12 minutes, just until slightly tender but still firm enough to hold their shape. Remove and set aside.

Step 2: Cook the Steak and Veggies : Heat 1 tbsp olive oil or butter in a large skillet over medium-high heat. Add the thinly sliced onions and cook for 3–4 minutes until softened. Add mushrooms (if using) and cook another 3–4 minutes until tender. Push vegetables to one side of the skillet and add another drizzle of oil. Add the sliced steak. Season with salt, pepper, and garlic powder. Cook for about 2–3 minutes, stirring occasionally, until just browned (do not overcook). Stir in Worcestershire sauce and soy sauce for added flavor. Mix everything together until well combined. Remove from heat.

Step 3: Assemble the Peppers : Place the roasted pepper halves in the baking dish. Spoon the steak and veggie mixture evenly into each pepper half. Top each with a slice of provolone cheese.

Step 4: Bake : Return the stuffed peppers to the oven. Bake for 10–12 minutes, or until the cheese is melted, bubbly, and slightly golden. Garnish with chopped parsley before serving.