Low Carb Philly Cheesesteak Casserole is the dinner I make when I’m craving a cheesy sub but want to keep things light and low on carbs. Picture juicy steak, sweet onions, tender peppers, and a bubbly blanket of provolone and mozzarella. It smells like a steak shop in your kitchen and tastes like comfort without the bread crash. If you’re juggling work, kids, and that “what’s for dinner” panic, this one is a total weeknight hero. It’s simple, cozy, and makes amazing leftovers. Let me show you how I make it, plus a few tricks so it turns out perfect every time.
Tips and Tricks
My goal with this dish is big cheesesteak flavor and a casserole that slices nicely. Here’s how I make that happen in a busy kitchen.
Slice the steak thin. It makes a huge difference. Partially freeze your steak for 20 to 30 minutes, then slice against the grain into thin strips. Thin slices cook fast and stay tender.
Use the right pan. A big skillet helps you get some color on the steak and veggies before they hit the oven. Color equals flavor. If the pan is crowded, cook in batches.
Cook the veggies until just tender. Overcooked peppers get mushy. I like them soft with a little bite left so they hold up in the casserole.
Season like a steakhouse. Salt, pepper, a little garlic and onion powder, and a splash of Worcestershire or coconut aminos bring that classic flavor. Taste and adjust before baking.
Cheese layering is key. I go half the cheese stirred into the filling so it binds everything, then the rest on top for that gooey, golden lid. Provolone for nostalgia, mozzarella for melt, and a little cream cheese for richness if I want it extra cozy.
Rest before slicing. Let the casserole sit 5 to 10 minutes after baking. It firms up so serving is clean and the juices redistribute.
If you love dishes like this, you’ll find tons of easy ideas in my low-carb recipes collection. They’re all simple, family friendly, and weeknight ready.
My neighbor said, “I didn’t even miss the roll.” He went back for seconds, then asked for the recipe. That’s my kind of review.
Variations
This casserole plays nicely with tweaks. You can make it spicier, cheesier, or even switch the protein with no fuss. Here are a few of my favorites.
Chicken cheesesteak. Slice chicken thighs thin and cook the same way. Thighs stay juicy and are super forgiving.
Ground beef shortcut. Brown lean ground beef with onions and peppers for busy nights. You still get that cheeseburger meets cheesesteak vibe, and it’s great for meal prep.
Mushroom lover. Add sliced mushrooms for an extra savory bite. Cook them separately first so they release water, then fold into the filling.
Cheese swaps. Provolone is classic, but try white American, Monterey Jack, or a mix with a little cheddar for sharpness. If you’re dairy sensitive, lactose-free provolone works surprisingly well.
Spice it up. A pinch of red pepper flakes, diced jalapeños, or a dash of hot sauce perks everything up without adding carbs.
Extra low-carb sidekick. Serve it with a side that leans cheesy and cozy, like this low carb pizza casserole on nights you’re feeding a crowd, or try handheld fun with these keto philly cheesesteak rolls when you want that classic vibe without bread.
How to Make Keto Philly Cheesesteak Casserole
This is the part where we bring it all together. It’s simple, fast, and built for real life. I like to keep it classic and let the steak and cheese lead the way.
What you need
- 1.25 to 1.5 pounds thinly sliced steak, like sirloin, ribeye, or flank
- 1 large onion, sliced
- 1 to 2 bell peppers, sliced (green for classic, or mix colors)
- 8 ounces mushrooms, sliced (optional)
- 2 cloves garlic, minced
- 1 teaspoon each salt and black pepper, plus more to taste
- 1 teaspoon onion powder and 1 teaspoon garlic powder
- 1 tablespoon Worcestershire or coconut aminos
- 4 ounces cream cheese, softened (optional for extra creaminess)
- 1.5 cups shredded provolone or mozzarella, divided
- 1 tablespoon olive oil or butter
Step by step
- Preheat your oven to 375 F. Grease a 9×13 baking dish.
- Heat a skillet over medium high with the oil. Sear the steak in batches until just browned. Season with salt and pepper. Do not overcook. Transfer to a bowl.
- In the same pan, cook the onions and peppers with a pinch of salt until tender crisp, about 5 to 7 minutes. Add mushrooms if using and cook until they release their liquid and brown slightly.
- Stir in the garlic, onion powder, garlic powder, and Worcestershire. Cook 30 seconds until fragrant.
- Turn off the heat. Add the steak back in and toss. Mix in half the shredded cheese and the cream cheese if using. Taste and adjust seasoning.
- Spread the mixture in your baking dish. Top with the remaining cheese.
- Bake 12 to 15 minutes until the cheese is melted and bubbly. For browned spots, broil 1 to 2 minutes. Let rest 5 to 10 minutes before serving.
Make ahead and storage tips
Assemble up to a day in advance, cover, and keep in the fridge. Bake when ready, adding a few extra minutes if it is cold from the fridge. Leftovers last 3 to 4 days and reheat well in a skillet or 350 F oven. You can also portion and freeze for up to 2 months. Thaw overnight and reheat until hot and melty.
For busy days when I do not want to turn on the oven, this slow cooker philly cheesesteak is another way to get that same flavor with almost no effort.
Serving Ideas
Let’s talk about the fun part. This dish is rich and savory, so I like pairings that feel fresh or cozy without heavy carbs. Here are simple ways to serve it.
- Spoon it over roasted or steamed cauliflower rice to catch all the cheesy juices.
- Serve with a crisp side salad with a bright vinaigrette to cut the richness.
- Fill lettuce cups or low carb tortillas for handheld bites.
- Layer onto roasted portobello caps for a fork and knife “open face” feeling.
- Round out the plate with a creamy side like cauliflower mac and cheese when you want comfort on comfort.
Sometimes I just add sliced dill pickles on the side for a tangy crunch. It works surprisingly well with the steak and cheese combo.
Is Steak Good for Keto?
Short answer: yes. Steak is naturally low in carbs and high in protein and fat, which fits perfectly with low carb eating. It is also rich in nutrients like iron, zinc, and B vitamins, especially B12, which supports energy and brain health.
For this Low Carb Philly Cheesesteak Casserole, I often use sirloin for a leaner result that still tastes great. Ribeye is the most tender and flavorful thanks to more marbling, but it comes with more calories. Flank works too if you slice thin and do not overcook. The key is thin slices and quick cooking, which keeps the texture tender.
If you are tracking macros, steak brings mostly protein and fat with practically no carbs. Pair it with low carb veggies like peppers, onions, and mushrooms and you have a balanced and filling meal. This is one reason this dish is a repeat at my house. It fills you up without the mid evening slump.
Common Questions
Can I use ground beef instead of steak?
Absolutely. Brown it well, drain any excess grease, then add the peppers, onions, and seasonings. It turns into a faster cheesesteak inspired bake that still hits all the notes.
What cheese melts best?
Provolone and mozzarella are my top picks for melt and flavor. If you want extra richness, stir in a little cream cheese or use a mix of provolone and Monterey Jack.
How do I avoid a watery casserole?
Cook the mushrooms separately so they release moisture, do not over salt early, and let the casserole rest before slicing. A hot oven and quick broil helps evaporate extra moisture.
Can I meal prep this?
Yes. Assemble it a day ahead or bake and portion it for lunches. It reheats well in a skillet or oven. If microwaving, cover loosely so the cheese does not dry out.
Is this spicy?
Not by default. Add red pepper flakes, hot sauce, or jalapeños if you like heat. Keep it mild for kids and spice individual portions to taste.
The Cozy, Low-Carb Casserole You’ll Make Again
If you’ve been chasing cheesesteak flavor without the roll, this Low Carb Philly Cheesesteak Casserole is the sweet spot. It is easy, hearty, and tastes just as good on day two. For more inspiration and alternate methods, I like how Keto Philly Cheesesteak Casserole – Kicking Carbs walks through variations, and the steps in Easy, Keto Low-Carb Philly Cheese Steak Casserole + {VIDEO} are great if you are a visual cook. Make it once and you’ll see why it is a keeper. I hope it brings that same cozy, satisfied feeling to your table that it brings to mine. 
Low Carb Philly Cheesesteak Casserole
Ingredients
Main Ingredients
- 1.25 to 1.5 pounds thinly sliced steak, like sirloin, ribeye, or flank Thin slices for best texture
- 1 large onion, sliced
- 1 to 2 pieces bell peppers, sliced (green or mixed colors)
- 8 ounces mushrooms, sliced (optional) Cook separately if used to avoid a watery casserole
- 2 cloves garlic, minced
- 1 teaspoon salt Adjust to taste
- 1 teaspoon black pepper Adjust to taste
- 1 teaspoon onion powder
- 1 teaspoon garlic powder
- 1 tablespoon Worcestershire or coconut aminos
- 4 ounces cream cheese, softened (optional) For extra creaminess
- 1.5 cups shredded provolone or mozzarella, divided Use half for the filling and half for topping
- 1 tablespoon olive oil or butter For cooking
Instructions
Preparation
- Preheat your oven to 375 F. Grease a 9×13 baking dish.
- Heat a skillet over medium high with the oil. Sear the steak in batches until just browned. Season with salt and pepper. Do not overcook. Transfer to a bowl.
- In the same pan, cook the onions and peppers with a pinch of salt until tender crisp, about 5 to 7 minutes. Add mushrooms if using and cook until they release their liquid and brown slightly.
- Stir in the garlic, onion powder, garlic powder, and Worcestershire. Cook for 30 seconds until fragrant.
- Turn off the heat. Add the steak back in and toss. Mix in half the shredded cheese and the cream cheese if using. Taste and adjust seasoning.
Baking
- Spread the mixture in your baking dish. Top with the remaining cheese.
- Bake for 12 to 15 minutes until the cheese is melted and bubbly. For browned spots, broil for 1 to 2 minutes.
- Let rest for 5 to 10 minutes before serving.
