Looking for a healthy twist on a classic Philly cheesesteak? This High-Protein, Low-Carb Philly Cheesesteak Casserole is packed with tender beef, sautéed peppers and onions, and gooey cheese, all while keeping it low-carb and high in protein.
Perfect for weeknight dinners, meal prep, or a hearty lunch, this casserole delivers all the flavor of a Philly cheesesteak without the bread.
Why You’ll Love This Philly Cheesesteak Casserole
✔ Low-carb, high-protein, and filling
✔ Packed with savory steak, peppers, and onions
✔ Gooey melted cheese for comfort without the carbs
✔ Easy to make in one pan or casserole dish
✔ Perfect for meal prep or family dinners
This casserole is hearty, flavorful, and guilt-free — a true weeknight winner.
Ingredients You’ll Need
- 1 lb thinly sliced beef (sirloin, ribeye, or roast beef)
- 1 medium onion, thinly sliced
- 1 green bell pepper, thinly sliced
- 1 red bell pepper, thinly sliced
- 2 cloves garlic, minced
- 2 tablespoons olive oil
- 1 teaspoon Worcestershire sauce
- Salt and pepper, to taste
- 1 cup shredded provolone cheese
- 1/2 cup shredded mozzarella cheese
- 1/4 cup grated Parmesan cheese
- Optional: 1/4 teaspoon red pepper flakes for heat
How to Make High-Protein, Low-Carb Philly Cheesesteak Casserole
Step 1: Preheat Oven
Preheat oven to 375°F (190°C).
Grease a 9×9-inch casserole dish or similar baking dish.
Step 2: Cook the Vegetables
In a large skillet, heat olive oil over medium heat.
Add onions and bell peppers and sauté for 5–7 minutes until softened.
Add garlic, salt, pepper, and red pepper flakes (if using) and cook 1 more minute.
Transfer vegetables to the prepared casserole dish.
Step 3: Cook the Beef
In the same skillet, cook thinly sliced beef with Worcestershire sauce until browned, about 3–5 minutes.
Season with salt and pepper, then layer the beef on top of the sautéed vegetables in the casserole dish.
Step 4: Add the Cheese
Sprinkle shredded provolone, mozzarella, and Parmesan cheese evenly over the beef and vegetables.
Step 5: Bake
Bake in the preheated oven for 15–20 minutes, until cheese is melted and bubbly.
Optional: broil for 1–2 minutes to achieve a golden, slightly crispy top.
Step 6: Serve
Serve hot, garnished with extra Parmesan or fresh parsley if desired.
Pair with a side salad or steamed veggies for a complete low-carb meal.
Tips for the Best Philly Cheesesteak Casserole
- Use thinly sliced steak for authentic Philly flavor and quick cooking.
- Don’t overcook the beef — it stays tender when added to the casserole.
- Feel free to swap provolone for your favorite low-carb cheese.
- Make ahead: assemble casserole and refrigerate; bake just before serving.
Easy Variations
1. Spicy Philly Cheesesteak
Add sliced jalapeños or hot sauce for a kick.
2. Low-FODMAP Option
Use garlic-infused oil instead of garlic cloves and omit onion if needed.
3. Slow Cooker Version
Layer ingredients in a slow cooker and cook on low for 3–4 hours, topping with cheese in the last 15 minutes.
4. Individual Servings
Divide ingredients into muffin tins or small ramekins for single-serve portions.
Storage & Make-Ahead
- Store leftovers in an airtight container in the fridge for up to 3 days.
- Reheat in the microwave or oven until warmed through.
- Freeze individual portions for up to 2 months; thaw in the fridge before reheating.