Prep the steak: Pat the sliced beef dry with paper towels.
Toss with 1/2 teaspoon salt, black pepper, smoked paprika, and oregano. If you have time, refrigerate for 15 minutes to help the seasoning sink in.
Cook the base: Warm your chosen base (quinoa, rice, beans, or cauliflower rice). For cauliflower rice, sauté with a little oil and a pinch of salt until tender and lightly browned, about 5–7 minutes.
Keep warm.
Sauté the veggies: Heat 1 tablespoon oil in a large skillet over medium-high heat. Add peppers and onions (and mushrooms, if using) with a pinch of salt. Cook, stirring occasionally, until softened and slightly charred at the edges, 7–9 minutes.
Stir in garlic during the last minute until fragrant. Transfer veggies to a bowl.
Sear the steak: Add the remaining 1 tablespoon oil to the same skillet. Increase heat to high.
Add the steak in a single layer. Cook without moving for 1–2 minutes to get color, then flip and cook another 1–2 minutes. You want browned edges but a tender center.
Season and deglaze: Reduce heat to medium.
Add Worcestershire sauce to the skillet and scrape up browned bits. Return peppers and onions to the pan and toss to combine. Taste and adjust salt and pepper.
Melt the cheese: Turn off the heat.
Lay provolone slices over the mixture or sprinkle on mozzarella. Cover the pan for 1–2 minutes until melted and gooey. For extra stretch, add a bit more cheese.
Assemble the bowls: Spoon your warmed base into bowls.
Top generously with the cheesesteak mixture. Finish with chopped parsley or green onions, and add hot sauce or a light yogurt drizzle if you like.