Keto Low Carb Philly Cheese Steak Casserole

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This keto-friendly casserole combines tender sirloin steak strips with sautéed green peppers, mushrooms, and onions for a flavorful base. Cream cheese and Worcestershire sauce create a rich, savory blend, topped with provolone and parmesan cheeses for melt-in-your-mouth goodness. Eggs and heavy cream blend into the layers, binding everything together while baking. Ready in about 40 minutes, it’s a perfect meal prep option that balances protein and creamy textures without extra carbs. Sear the steak briefly, soften the veggies, then assemble and bake until cheese bubbles and flavors meld.

Barbara Chef
Updated on Fri, 20 Feb 2026 00:02:34 GMT
A dish of meat and vegetables. Pin it
A dish of meat and vegetables. | gracefulflavors.com

This Keto Low-Carb Philly Cheese Steak Casserole makes a satisfying and simple dinner that combines the rich flavors of sirloin steak, creamy cheese, and sautéed vegetables. It’s perfect for anyone who wants a hearty meal that fits low-carb and keto lifestyles without giving up flavor or comfort.

I first made this casserole on a busy evening when I wanted something filling but fast. Now it’s my go-to for when I want the taste of a Philly cheesesteak with zero fuss.

Ingredients

  • Sirloin steak: One and a half pounds sliced thin for quick cooking and great texture; choose well-marbled cuts for flavor
  • Steak seasoning: Such as Montreal Steak Seasoning adds a robust, savory punch that lifts the meat
  • Green peppers: Bring freshness and a gentle crunch; look for firm, glossy peppers with bright color
  • Mushrooms: Provide earthiness and soak up all the savory juices; cremini or white button work beautifully
  • Onions and garlic: Form the aromatic backbone, softening in the pan to sweet and fragrant
  • Cream cheese: Adds a silky creaminess that binds the casserole and keeps it moist
  • Worcestershire sauce: Enhances the umami with its tangy depth
  • Eggs and heavy cream: Create a rich custard that holds the casserole together
  • Shredded Parmesan Reggiano: Delivers a salty bite and enhances the cheesy flavor
  • Provolone cheese slices: On top melt into a bubbly, golden crust

Step-by-Step Instructions

Preheat the Oven:
Set your oven to 350 degrees Fahrenheit and allow it to come to temperature while you prepare everything else.
Sear the Steak:
Heat a skillet over medium-high heat and add the sliced sirloin steak. Sprinkle steak seasoning along with salt and pepper directly on the meat. Cook the steak strips for 2 to 3 minutes, turning to brown both sides but not overcooking. This quick sear locks in juices and builds the flavor base.
Sauté the Vegetables:
Add the chopped green peppers, onions, garlic, and mushrooms to the skillet with the steak. Cook everything together until the vegetables become soft and the steak is no longer pink. This step develops the savory sweet blend the casserole needs.
Drain Excess Fat:
Once the meat and vegetables are cooked, carefully pour off any excess fat or liquid from the pan. This is key to preventing a watery texture in your casserole.
Melt in Cream Cheese and Worcestershire:
Stir in the Worcestershire sauce and cream cheese to the skillet. Continue cooking until the cream cheese melts fully and combines with the ingredients, creating a rich, creamy mixture. Remove the skillet from the heat.
Prepare the Egg Mixture:
In a separate bowl, whisk together the eggs, shredded Parmesan Reggiano, and heavy cream until smooth. This mixture will set the casserole while adding richness.
Assemble and Bake:
Spray an 8x11 or 9x9 baking dish with oil or cooking spray. Pour the steak and vegetable mixture into the dish, then drizzle the egg and cheese liquid evenly over it. Arrange the provolone slices on top. Bake uncovered for 15 to 20 minutes until the cheese bubbles and starts to brown lightly. Let the casserole cool a little before serving to allow it to set perfectly.
A close up of a cheese and mushroom pizza. Pin it
A close up of a cheese and mushroom pizza. | gracefulflavors.com

This casserole reminds me of a chilly evening when my family gathered around the table sharing stories and savoring every bite together—it’s comfort food that brings people close.

Storage Tips

Store leftovers tightly covered in the refrigerator for up to four days. Reheat gently in the oven or microwave to keep the cheese from toughening. It also freezes beautifully; thaw overnight in the fridge before reheating.

Ingredient Substitutions

Flank steak or ribeye can replace sirloin if you want a different texture or fattier bite. For dairy-free versions, consider a cream cheese substitute and omit the Parmesan, though the flavor will differ. Bell peppers can be swapped for poblano or even mild jalapeños for a zip.

Serving Suggestions

Serve this casserole with a crisp green salad or steamed low-carb veggies like broccoli, asparagus, or cauliflower rice to round out the meal. A side of pickles or sauerkraut adds a pleasant tang against the richness.

A casserole with meat, cheese, and peppers. Pin it
A casserole with meat, cheese, and peppers. | gracefulflavors.com

Frequently Asked Questions

→ What steak cuts work best for this dish?

Sirloin is great for tender, quick cooking, but flank steak also works well when sliced thin for this casserole.

→ How can I prevent the casserole from becoming soggy?

Drain any excess fat or liquid from the skillet after cooking the steak and veggies to keep the casserole firm and not watery.

→ Can I substitute the cheeses used here?

Provolone and parmesan provide rich melt and flavor, but you can try mozzarella or cheddar for a different twist.

→ Is this dish suitable for meal prep?

Absolutely. It stores well in containers and reheats nicely, making it convenient for lunches or dinners during the week.

→ What sides pair well with this casserole?

Light salads, steamed vegetables, or cauliflower rice complement the rich, cheesy casserole nicely without adding many carbs.

→ How long should I bake the casserole?

Bake at 350°F for about 15-20 minutes, until the cheese is bubbly and slightly golden on top.

Keto Low Carb Philly Steak

Hearty dish with sirloin, peppers, mushrooms, and creamy cheese perfect for low-carb dinners or meal prep.

Prep Time
10 Minutes
Cook Time
30 Minutes
Total Time
40 Minutes
By: Barbara

Category: Hearty Mains

Difficulty: Easy

Cuisine: American

Yield: 6 Servings

Dietary: Low-Carb, Gluten-Free

Ingredients

→ Beef and Seasoning

01 1 ½ pounds sirloin steak, thinly sliced
02 1 teaspoon Montreal steak seasoning
03 Salt and black pepper, to taste

→ Vegetables

04 1 cup green bell peppers, sliced
05 1 cup mushrooms, sliced
06 1 cup onion, chopped
07 2 cloves garlic, chopped

→ Dairy and Sauces

08 2 ounces cream cheese
09 1 teaspoon Worcestershire sauce
10 2 eggs
11 ½ cup heavy whipping cream
12 ½ cup shredded Parmesan Reggiano cheese
13 4-5 slices provolone cheese, sliced into small pieces

Instructions

Step 01

Preheat the oven to 350°F (175°C).

Step 02

Heat a skillet over medium-high heat and add the sliced sirloin steak. Season with Montreal steak seasoning, salt, and pepper. Cook steak for 2 to 3 minutes, flipping until browned on both sides.

Step 03

Add green bell peppers, onion, garlic, and mushrooms to the skillet. Sauté until vegetables are softened and the steak is no longer pink.

Step 04

Carefully drain any excess fat or liquid from the skillet to prevent the casserole from becoming watery.

Step 05

Stir in the Worcestershire sauce and cream cheese into the skillet mixture. Cook until the cream cheese is fully melted and incorporated.

Step 06

In a medium bowl, whisk together eggs, shredded Parmesan cheese, and heavy whipping cream until smooth.

Step 07

Lightly grease an 8x11 or 9x9 inch baking dish with oil or cooking spray. Transfer the steak and vegetable mixture into the dish, then pour the egg and cheese custard evenly over the top. Arrange the provolone cheese slices over the surface.

Step 08

Bake in the preheated oven for 15 to 20 minutes, or until the cheese is bubbly and lightly golden.

Step 09

Remove from oven and allow to cool slightly before serving.

Notes

  1. Draining excess fat after cooking the steak and vegetables is essential to avoid a soggy casserole base.

Tools You'll Need

  • 9x13 inch baking dish
  • Skillet
  • Mixing bowl
  • Cooking spray or oil

Allergy Information

Please check ingredients for potential allergens and consult a health professional if in doubt.
  • Contains dairy and eggs

Nutrition Facts (Per Serving)

It is important to consider this information as approximate and not to use it as definitive health advice.
  • Calories: 387
  • Total Fat: ~
  • Total Carbohydrate: ~
  • Protein: ~