If you love the flavors of a classic Philly cheesesteak but want to keep carbs in check, this casserole hits the spot. It’s meaty, cheesy, and loaded with tender peppers and onions, all baked into a bubbly, golden pan that feeds a crowd. The prep is simple, the ingredients are easy to find, and the leftovers taste even better the next day.
It’s the kind of dish you can serve to keto and non-keto eaters alike without anyone feeling like they’re missing out.
Keto Philly Cheesesteak Casserole - Comforting, Low-Carb, and Weeknight Easy
Ingredients
- 1.5 pounds ground beef (85–90% lean) or thinly sliced sirloin
- 2 tablespoons olive oil or avocado oil, divided
- 1 large yellow onion, thinly sliced
- 2 bell peppers (green or a mix of green and red), thinly sliced
- 8 ounces mushrooms, sliced (optional but recommended)
- 3 cloves garlic, minced
- 1 teaspoon kosher salt, plus more to taste
- 1/2 teaspoon black pepper
- 1 teaspoon onion powder
- 1 teaspoon garlic powder
- 1/2 teaspoon smoked paprika (optional for a deeper flavor)
- 4 ounces cream cheese, softened
- 1/2 cup heavy cream
- 1 teaspoon Worcestershire sauce (check for low-sugar)
- 1 tablespoon Dijon mustard
- 1.5 cups shredded provolone or mozzarella, divided
- 1/2 cup shredded Parmesan (optional, for extra flavor and browning)
- Fresh parsley, chopped (for garnish)
Instructions
- Preheat and prep: Heat your oven to 375°F (190°C). Grease a 9x13-inch baking dish with a little oil or butter.
- Cook the vegetables: In a large skillet over medium-high heat, warm 1 tablespoon oil. Add the onions and peppers. Cook 6–8 minutes, stirring occasionally, until softened and lightly browned. If using mushrooms, add them in the last 4–5 minutes. Season with a pinch of salt and pepper. Transfer to a bowl.
- Brown the beef: In the same skillet, add the remaining oil and the ground beef (or sliced sirloin). Break up the beef and cook until browned and no longer pink, about 6–8 minutes. Drain excess grease if needed.
- Season the meat: Add minced garlic, salt, pepper, onion powder, garlic powder, and smoked paprika. Cook 1 minute until fragrant. Turn heat to low.
- Make it creamy: Stir in cream cheese until melted and silky. Add heavy cream, Worcestershire, and Dijon. Simmer gently 1–2 minutes to thicken slightly. Taste and adjust salt and pepper.
- Layer the casserole: Spread the meat mixture evenly in the baking dish. Top with the sautéed peppers, onions, and mushrooms.
- Add cheese: Sprinkle 1 cup shredded provolone (or mozzarella) evenly over the top, then add Parmesan if using. Reserve the remaining 1/2 cup cheese for later.
- Bake: Place the dish in the oven and bake for 15 minutes until the cheese is melted and edges are bubbling.
- Finish and broil: Remove, add the remaining 1/2 cup cheese, and switch the oven to broil. Broil 1–2 minutes until the top is golden and spotty brown. Watch closely to prevent burning.
- Rest and serve: Let the casserole sit 5–10 minutes so it sets. Garnish with chopped parsley. Serve with a simple green salad or roasted broccoli.
Why This Recipe Works
- All the flavor, fewer carbs: You get the steak, peppers, onions, and melty cheese—just without the bread.
- One-pan convenience: Sauté the veggies and beef, layer, and bake. Minimal mess and maximum payoff.
- Customizable: Use ground beef or sliced steak, swap cheeses, or add mushrooms. It adapts to what you have.
- Perfect texture: Baking lets the cheese melt into the meat and vegetables, giving you that classic cheesesteak richness in a scoopable form.
- Meal prep friendly: Holds up well in the fridge and reheats without drying out.
Ingredients
- 1.5 pounds ground beef (85–90% lean) or thinly sliced sirloin
- 2 tablespoons olive oil or avocado oil, divided
- 1 large yellow onion, thinly sliced
- 2 bell peppers (green or a mix of green and red), thinly sliced
- 8 ounces mushrooms, sliced (optional but recommended)
- 3 cloves garlic, minced
- 1 teaspoon kosher salt, plus more to taste
- 1/2 teaspoon black pepper
- 1 teaspoon onion powder
- 1 teaspoon garlic powder
- 1/2 teaspoon smoked paprika (optional for a deeper flavor)
- 4 ounces cream cheese, softened
- 1/2 cup heavy cream
- 1 teaspoon Worcestershire sauce (check for low-sugar)
- 1 tablespoon Dijon mustard
- 1.5 cups shredded provolone or mozzarella, divided
- 1/2 cup shredded Parmesan (optional, for extra flavor and browning)
- Fresh parsley, chopped (for garnish)
Step-by-Step Instructions
- Preheat and prep: Heat your oven to 375°F (190°C).
Grease a 9×13-inch baking dish with a little oil or butter.
- Cook the vegetables: In a large skillet over medium-high heat, warm 1 tablespoon oil. Add the onions and peppers. Cook 6–8 minutes, stirring occasionally, until softened and lightly browned.
If using mushrooms, add them in the last 4–5 minutes. Season with a pinch of salt and pepper. Transfer to a bowl.
- Brown the beef: In the same skillet, add the remaining oil and the ground beef (or sliced sirloin).
Break up the beef and cook until browned and no longer pink, about 6–8 minutes. Drain excess grease if needed.
- Season the meat: Add minced garlic, salt, pepper, onion powder, garlic powder, and smoked paprika. Cook 1 minute until fragrant.
Turn heat to low.
- Make it creamy: Stir in cream cheese until melted and silky. Add heavy cream, Worcestershire, and Dijon. Simmer gently 1–2 minutes to thicken slightly.
Taste and adjust salt and pepper.
- Layer the casserole: Spread the meat mixture evenly in the baking dish. Top with the sautéed peppers, onions, and mushrooms.
- Add cheese: Sprinkle 1 cup shredded provolone (or mozzarella) evenly over the top, then add Parmesan if using. Reserve the remaining 1/2 cup cheese for later.
- Bake: Place the dish in the oven and bake for 15 minutes until the cheese is melted and edges are bubbling.
- Finish and broil: Remove, add the remaining 1/2 cup cheese, and switch the oven to broil.
Broil 1–2 minutes until the top is golden and spotty brown. Watch closely to prevent burning.
- Rest and serve: Let the casserole sit 5–10 minutes so it sets. Garnish with chopped parsley.
Serve with a simple green salad or roasted broccoli.
How to Store
- Refrigerate: Cool completely, then cover and store for up to 4 days.
- Freeze: Portion into airtight containers and freeze for up to 2 months. Thaw overnight in the fridge.
- Reheat: Warm in a 325°F (165°C) oven for 15–20 minutes, or microwave in 60–90 second bursts. Add a splash of cream if reheating seems dry.
Health Benefits
- Low carb, high satisfaction: Skipping the roll keeps net carbs low while delivering plenty of protein and fat to keep you full.
- Balanced fats: Using olive or avocado oil and a mix of cheeses provides a blend of saturated and monounsaturated fats.
- Micronutrients from veggies: Peppers, onions, and mushrooms bring vitamin C, B vitamins, potassium, and fiber.
- Blood sugar friendly: With minimal carbs and solid protein, this dish helps avoid sharp spikes in blood glucose for most people.
What Not to Do
- Don’t skip browning: Rushing the vegetables or meat robs the dish of that savory, caramelized flavor.
- Don’t drown in liquid: Too much cream or not draining excess fat can make the casserole soupy.
Stick to the amounts listed.
- Don’t overbake: The cheese can turn rubbery if baked too long. Bake until melted, then finish briefly under the broiler.
- Don’t forget to rest: Letting it sit helps the creamy mixture set, making it easier to slice and serve.
Alternatives
- Protein swaps: Use thinly sliced ribeye for a classic feel, ground turkey for a lighter option, or shaved roast beef for speed.
- Dairy-free: Replace cream cheese and heavy cream with a thick, unsweetened coconut cream and use a dairy-free melting cheese alternative. Add extra seasoning to make up for flavor differences.
- Veggie boost: Add spinach, zucchini ribbons, or cauliflower rice.
Sauté first to remove moisture.
- Cheese variations: Provolone is traditional, but mozzarella, Monterey Jack, or a provolone–cheddar mix also works. For extra tang, add a few slices of provolone on top just before broiling.
- Spice it up: Add red pepper flakes, jalapeños, or a splash of hot sauce to the meat mixture.
FAQ
Can I use steak instead of ground beef?
Yes. Thinly slice sirloin or ribeye against the grain.
Sear quickly over high heat until just browned, then proceed with the sauce and baking steps. Avoid overcooking to keep it tender.
Is Worcestershire sauce keto?
Most brands have small amounts of sugar but are used in tiny quantities. At 1 teaspoon for the whole casserole, the carb impact is minimal.
Check the label and choose a lower-sugar brand if you’re strict.
How can I make this casserole even lower in carbs?
Use only green bell peppers (slightly lower in carbs than red), skip onions or use half, and avoid mushrooms if you’re counting tightly. You can also reduce the cream to 1/3 cup and increase cream cheese for thickness.
What can I serve with it?
Keep it simple: a side salad with olive oil and vinegar, roasted asparagus, or sautéed green beans. If you’re not strict keto, a small portion of roasted sweet peppers works well.
Why is my casserole watery?
Likely excess moisture from veggies or not draining the meat.
Sauté vegetables until most liquid evaporates and drain beef if it’s very fatty. Also, measure cream carefully and let the casserole rest before serving.
Can I assemble it ahead of time?
Yes. Assemble up to the cheese layer, cover, and refrigerate for up to 24 hours.
Add 5–10 extra minutes to the bake time if baking straight from the fridge.
What cheese is best?
Provolone is classic for that Philly flavor. Mozzarella melts beautifully, and Parmesan adds a savory kick. A mix of provolone and mozzarella is a great balance of flavor and melt.
How do I keep the beef from drying out?
Don’t overcook it during the browning stage—stop once it’s no longer pink.
The cream cheese and cream will keep it moist as it bakes.
Can I make it in a skillet and skip baking?
You can. After melting the cheese into the meat and veggies, cover and cook on low heat for 5 minutes to melt everything together. You’ll miss the browned top, but it will still taste great.
Wrapping Up
This Keto Philly Cheesesteak Casserole brings everything you love about the original—savory beef, melty cheese, and sweet peppers—without the bread.
It’s easy, flexible, and perfect for busy nights or meal prep. Keep the ingredients on hand, and you can have a comforting, low-carb dinner on the table with minimal effort. Once you try it, it’s bound to become a weeknight regular.