Preheat oven to 375°F (190°C).
- In a large skillet, heat olive oil or butter over medium heat. Add sliced bell peppers and onion. Sauté for 5–7 minutes until soft. Add garlic and cook for 1 more minute. Remove and set aside.
- In the same skillet, cook steak slices until browned. Drain any excess fat.
- Season steak with Worcestershire sauce, salt, pepper, and optional Italian seasoning.
- Add cream cheese and stir until melted and combined with the steak.
- Return sautéed peppers and onions to the skillet. Stir to combine.
- If using a base (pasta, potatoes, or cauliflower rice), stir it in now.
- Transfer mixture to a greased 9×13-inch baking dish. Top with provolone and mozzarella cheese.
- Bake uncovered for 20–25 minutes, or until cheese is melted and bubbly. Broil for 2–3 minutes if desired for a golden top.
- Let rest for 5 minutes before serving.