This keto Philly cheesesteak skillet is a high-protein, low-carb meal that can be made in 30 minutes in one pan! It's packed full of flavor with tender sirloin steak and charred veggies, including sliced bell pepper, onion and mushrooms. And it's topped with gooey, melted mozzarella cheese! Trust us, you'll love this simple all-in-one dish since it's so yummy and easy to make!

Man, this low-carb Philly cheesesteak skillet is one delicious weeknight meal! It's surprising how much flavor oozes from this dish considering there aren't that many ingredients. Ingredients include sirloin steak, green bell pepper, sliced onions, white mushrooms, garlic and shredded mozzarella cheese.
To make this meal high-protein and keto-friendly, we use sirloin steak and carefully balanced the amount of veggies and cheese. It's only 6.8 net carbs and 40 percent protein per serving. You'll find that it's deliciously satisfying and filling for a quick weeknight meal.
Plus, this meal is a breeze to make. It's done in just 30 minutes, has only 8 ingredients, and uses just one pan! Perfect weeknight meal if you ask us!
What is a Philly Cheesesteak?
A Philly cheesesteak, originating from Philadelphia, Pennsylvania, is a sandwich in which thinly sliced beef (typically ribeye steak) is placed in a toasted hoagie roll and topped with melted cheese (typically provolone cheese or Cheez Whiz). Most often, a cheesesteak sandwich includes caramelized onions. Some variations of cheesesteak include sliced bell peppers and mushrooms.
This skillet is a twist on the cheesesteak sandwich since it's simply eaten as a dish and not served in a sandwich. And you won't miss the sandwich with this delicious skillet!
Ingredients

Just 8 ingredients in this low-carb Philly cheesesteak skillet!
- Steak: Although Philly cheesesteak sandwiches are typically made with ribeye, our favorite cut for this skillet is sirloin. It's tender, higher in protein, easy to slice and much cheaper than ribeye!
- Onions: Onions are a must! We carefully balanced the amount of onions, so the dish remains high in protein and low in carbs.
- Mushrooms: Although not everyone includes mushrooms in Philly cheesesteaks, they sure add a lot to this skillet. We purchase pre-sliced white mushrooms to make it easy. You could also use cremini mushrooms if you like.
- Bell pepper: Again, not everyone includes bell pepper in a cheesesteak, but we find that it adds to the texture and makes the skillet more of a complete dish. Just half a bell pepper, sliced, is all that's needed!
- Shredded, mozzarella cheese: Provolone and Cheez Whiz are commonly used in Philly cheesesteaks, but we use shredded mozzarella since it's something most people keep in their fridge. Plus, it melts well in this skillet and is a high-protein cheese.
How to Make
Just a few easy steps in making this keto Philly cheesesteak:
STEP 1 - SLICE STEAK INTO THIN PIECES: A Philly cheesesteak uses thin slices of tender beef. To slice the beef as thin as possible, most experts recommend popping the beef in the freezer for at least 20 minutes. After, remove from freezer and slice very thinly. Season with salt and pepper and set aside.
STEP 2 - COOK THE VEGGIES: In a large skillet over medium-high heat, add ½ tablespoon of oil. Then, add sliced pepper, onion, and mushrooms. Cook until peppers are tender and mushrooms and onions begin to brown, about 5 minutes. Season with salt and pepper. Remove veggies from skillet and set aside on separate plate.


STEP 3 - COOK THE STEAK: Return skillet back to medium high-heat and add ½ tablespoon oil. Add sirloin slices to skillet, ensuring space between each (you'll likely need to do in two batches) and cook for one to two minutes per side, until browned. When done, remove from skillet and place on separate plate.
STEP 4 - COMBINE INGREDIENTS: Place skillet on medium heat and return veggies and steak back to pan. Add minced garlic and stir until ingredients are combined.


STEP 5 - ADD CHEESE: Remove pan from heat and sprinkle shredded cheese over the top.
STEP 6 - BROIL: Transfer skillet to oven and broil on low until cheese is melted, roughly two minutes. Serve immediately.


More About High-Protein Meals
We love high-protein meals since they help keep you full for longer periods of times. Therefore, you’re less likely to overeat or snack between meals. Wikipedia defines a high protein diet as more than 20% of calories from protein while DietDoctor uses 25% go 35% of calories. For more about high protein, DietDoctor has an extensive guide to high-protein meals.
RECIPE FAQ
Ribeye is typically used in a Philly cheesesteak. However, it is an expensive cut of steak. Other options include sirloin and flank steak. We had the best results with sirloin steak. Plus, it's the highest in protein.
Philly cheesesteaks are typically made with yellow onion. You can eat yellow onions in moderation on a low-carb and keto diet. We limited the onions in this dish to ¼ cup to keep the carbs low.
Yes, but this will reduce the percent of protein in this recipe. You can place 3 to 4 slices of provolone cheese over the dish and then broil (similar to the mozzarella) until melted.
Yes, this dish can be stored in an airtight container in the refrigerator for up to 3 days.
RELATED RECIPES
If you try this recipe, we would love to hear your feedback! Leave a comment, rate it, and tag @lowcarbsimplified on your photo of this recipe on Instagram or Facebook. We hope you enjoy this recipe as much as we do!
Recipe

Philly Cheesesteak Skillet (High-Protein / Keto)
Ingredients
- 1 pound sirloin steak
- Salt and pepper to season
- 1 tablespoon olive oil
- ½ medium green bell pepper ribs and seeds removed and cut into 2-inch long strips
- ¼ cup yellow onion sliced
- 4 ounces pre-sliced white mushrooms
- 4 garlic cloves minced
- ½ cup shredded mozzarella
Instructions
- Prepare the steak: Place steak in freezer for 20 minutes (makes it easier to slice meat thinly). Remove from freezer and slice very thinly. Season with salt and pepper and set aside.
- Cook the veggies: In a large skillet over medium-high heat, add ½ tablespoon oil. Then, add sliced pepper, onion, and mushrooms. Cook until peppers are tender and mushrooms and onions begin to brown, about 5 minutes. Season with salt and pepper. Remove veggies from skillet and set aside on separate plate.
- Cook the steak: Return skillet back to medium high-heat and add ½ tablespoon oil. Add sirloin slices to skillet, ensuring space between each (you'll likely need to do in two batches) and cook for one to two minutes per side, until browned. When done, remove from skillet and place on separate plate.
- Combine and finish: Place skillet on medium heat and return veggies and steak back to pan. Add minced garlic and stir until ingredients are combined. Season with salt and pepper as needed. Remove from heat and sprinkle shredded cheese over the top. Transfer skillet to oven and broil on low until cheese is melted, roughly one to two minutes. Serve immediately.
Notes
- To slice the beef as thin as possible, most experts recommend popping the beef in the freezer for at least 20 minutes.
- Slice the beef against the grain when slicing thinly.
- Slices of beef should be between 2 to 3 inches in length.
- Store leftovers in an air tight container in the fridge for up to 3 days.
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