Prep the steak: If slicing at home, place the steak in the freezer for 30–40 minutes to firm up.
Slice thinly against the grain. Pat dry and season with salt, pepper, and garlic powder.
Cook the veggies: Heat 1 tablespoon oil in a large skillet over medium-high. Add onions and peppers with a pinch of salt.
Sauté 5–7 minutes until softened and lightly charred. Add mushrooms and cook 3–4 minutes more. Stir in minced garlic for 30 seconds.
Transfer vegetables to a bowl.
Sear the steak: Add remaining oil and butter to the same skillet. Increase heat to high. Spread the steak in a single layer and let it sear undisturbed for 1–2 minutes.
Toss and cook another 1–2 minutes until just cooked through. Season with smoked paprika if using.
Deglaze: Pour in beef broth to lift the browned bits. Let it simmer 30–60 seconds to reduce slightly.
Combine: Return the peppers, onions, and mushrooms to the skillet and toss with the steak.
Taste and adjust salt and pepper.
Add the cheese: Lay provolone slices over the top, cover the pan, and let them melt for 1–2 minutes. Or stir in cream cheese with a splash of broth for a light sauce, then sprinkle shredded provolone and melt.
Optional base: If using cauliflower rice or shredded cabbage, sauté it in a separate pan with a little oil and salt until tender-crisp (5–7 minutes). Keep it simple so the cheesesteak flavors shine.
Serve: Spoon the steak-and-veg mixture into bowls, cheese and all.
Add the cauliflower rice or cabbage if using. Finish with chopped parsley and freshly cracked pepper.