This quick high-protein casserole layers ground beef, sautéed mushrooms, melted Swiss cheese, and creamy cottage cheese for a steakhouse burger taste without the drive-thru. Perfect for busy weeknights!

Ingredients

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Instructions

Step 1

Preheat your oven to 375°F (190°C). While the oven heats, gather all your ingredients. This mise en place approach ensures a smooth cooking process. You’ll need a large skillet (preferably cast iron or non-stick) and a 9×13-inch baking dish (or a 2.5-quart casserole dish). Lightly grease the baking dish with non-stick spray or a thin layer of olive oil. This prevents sticking and makes cleanup easier. The oven needs to be fully preheated so that when the casserole goes in, it starts cooking immediately, ensuring even melting of the cheese and proper bubbling of the cottage cheese mixture.

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Step 2

Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Once the oil shimmers (about 30 seconds), add the sliced mushrooms in a single layer. Do not overcrowd the pan—if necessary, cook in batches. Let the mushrooms cook undisturbed for 3-4 minutes until they release their moisture and develop a deep golden-brown color on one side. Stir and continue cooking for another 2-3 minutes until all mushrooms are browned. This browning, known as the Maillard reaction, creates savory, umami flavor. Season with a pinch of salt and pepper. Transfer the mushrooms to a plate and set aside.

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Step 3

In the same skillet, add the diced onion and cook over medium heat for 3-4 minutes, stirring occasionally, until softened and translucent. Add the minced garlic and cook for 30 seconds until fragrant. Be careful not to burn the garlic, as it becomes bitter. Now add the ground beef, breaking it apart with a wooden spoon or spatula. Cook for 5-7 minutes, stirring occasionally, until the beef is no longer pink and has developed some brown bits on the bottom of the pan. Drain any excess fat if necessary (lean beef may not need draining). The fond on the bottom of the skillet is flavor gold—don’t scrub it off.

Step 4

Reduce heat to low. Stir in the Worcestershire sauce, Dijon mustard, dried thyme, salt, and pepper. Mix well to coat the meat. Then pour in the beef broth and scrape the bottom of the skillet with a wooden spoon to deglaze, lifting all those browned bits into the sauce. Let the mixture simmer for 2 minutes until slightly thickened. Remove from heat. The broth adds moisture and richness, ensuring the casserole doesn’t dry out during baking.

Step 5

Spoon the beef mixture into the prepared baking dish, spreading it evenly. Top with the reserved sautéed mushrooms, distributing them evenly over the meat. In a small bowl, combine the cottage cheese with half of the shredded Swiss cheese and all of the mozzarella. Mix gently. Dollop spoonfuls of the cottage cheese mixture over the mushrooms, then gently spread it into an even layer. The cottage cheese will create a creamy, protein-packed topping that bakes into a luscious, cheesy crust.

Step 6

Sprinkle the remaining Swiss cheese evenly over the top. Place the casserole in the preheated oven and bake for 15 minutes, or until the cheese is melted and bubbly and the edges are lightly golden. If you want a deeper golden crust, switch the oven to broil for the last 1-2 minutes, watching carefully to prevent burning. Let the casserole rest for 5 minutes before serving. This resting time allows the casserole to set, making it easier to slice and serve. Garnish with fresh chopped parsley for a pop of color and freshness.

For best results

  • Choose the right ground beef: For a macro-friendly casserole, opt for lean ground beef with 90/10 or 93/7 lean-to-fat ratio. This provides plenty of protein without excessive saturated fat. If you use higher-fat beef (like 80/20), be sure to drain the fat after browning to keep the dish from becoming greasy. The cottage cheese adds creaminess, so you won't miss the extra fat.
  • Don't skip browning the mushrooms: Mushrooms are mostly water, and if you don't give them enough heat and time, they'll steam instead of brown. To achieve that deep, meaty flavor, cook them in a single layer over medium-high heat and resist the urge to stir too often. Let them develop a golden crust before flipping. This process concentrates their natural glutamates, enhancing the overall umami of the casserole.
  • Low-fat cottage cheese works best: Use 2% or 4% milkfat cottage cheese. Nonfat cottage cheese can be watery and may separate during baking, while full-fat (4% or higher) yields a richer result but adds more calories. For the best texture, look for cottage cheese with a creamy, small-curd consistency. If you have time, drain the cottage cheese in a fine-mesh sieve for 15 minutes to remove excess liquid and prevent a watery casserole.
  • Make it ahead for meal prep: This casserole is excellent for meal prep. Assemble the casserole completely (without baking) up to 24 hours in advance, cover tightly with foil, and refrigerate. When ready to bake, add 5-10 minutes to the baking time since the dish starts cold. You can also freeze the unbaked casserole for up to 3 months. Thaw overnight in the refrigerator before baking. The baked casserole keeps in the fridge for up to 4 days. Reheat individual portions in the microwave or oven.
  • Customize the cheese blend: Swiss cheese is classic for a mushroom Swiss burger, but feel free to experiment. Gruyère adds a nutty, slightly sweet flavor and melts beautifully. Provolone or white cheddar also work well. For a lower-fat option, reduce the Swiss and increase the mozzarella. The cottage cheese provides the creamy base, so you can adjust the top cheese to your taste without sacrificing texture.
  • Add vegetables for extra nutrition: Boost the veggie content by mixing in a cup of chopped spinach or kale with the beef during the last minute of cooking—they'll wilt down and blend seamlessly. You can also add a layer of roasted bell peppers or zucchini slices between the beef and mushrooms. Just be sure to sauté or roast them first to remove excess moisture, so the casserole doesn't become soggy.

Variations

  • Low-Carb/Keto Adaptation: To make this casserole keto-friendly, replace the Worcestershire sauce (which contains sugar) with a sugar-free version or coconut aminos. Use full-fat cottage cheese or substitute with cream cheese mixed with a splash of heavy cream. Increase the fat content by using 80/20 ground beef and adding extra cheese. Serve with a side of roasted broccoli or cauliflower rice to keep carbs low. Each serving will have approximately 5-7g net carbs.
  • Turkey or Chicken Version: Swap the ground beef for lean ground turkey or chicken. Since poultry is leaner, add 1 tablespoon of olive oil to the skillet when browning to prevent dryness. You may also need to increase the beef broth to 3/4 cup to maintain moisture. The flavor profile remains delicious, with a slightly lighter taste. This variation reduces calories to about 320 per serving while keeping protein high.
  • Vegetarian Option: Replace the ground beef with 1.5 cups of cooked lentils or a plant-based ground meat substitute (like Beyond Meat or crumbled tofu). Use vegetable broth instead of beef broth. For the cheese, ensure your Swiss and mozzarella are vegetarian-friendly (many are made with microbial rennet). The cottage cheese can be substituted with a plant-based cottage cheese alternative or blended silken tofu with nutritional yeast for a cheesy flavor. This version is still high in protein but suitable for vegetarians.
  • Spicy Southwest Twist: Add 1 teaspoon of chili powder, 1/2 teaspoon of cumin, and a pinch of cayenne pepper to the beef mixture. Swap the Swiss cheese for pepper jack cheese and replace the mushrooms with a can of drained and rinsed black beans. Top with sliced jalapeños before baking. Serve with a dollop of Greek yogurt or sour cream. This variation brings a smoky, spicy kick that pairs well with the creamy cottage cheese.
  • Add Bacon for Extra Smokiness: Cook 4 slices of bacon until crispy, then crumble. Stir half of the bacon into the beef mixture and reserve the rest for topping before baking. The bacon adds a smoky depth that complements the Swiss cheese and mushrooms beautifully. This variation increases the calorie count slightly but adds irresistible flavor. For a healthier twist, use turkey bacon.
  • Cheesy Onion Topping: For an extra layer of flavor, caramelize an additional onion in the skillet after cooking the mushrooms (about 10 minutes over medium-low heat) and layer it over the mushrooms before adding the cottage cheese mixture. You can also mix 1/4 cup of crispy fried onions (like French's) into the cheese topping for a crunchy texture. This adds a sweet, savory note reminiscent of a classic Swiss burger.

Nutrition

  • Calories385 kcal
  • Total Fat18g
  • Saturated Fat9g
  • Cholesterol95mg
  • Sodium620mg
  • Total Carbohydrates10g
  • Dietary Fiber2g
  • Sugars4g
  • Protein42g

Common Questions

Can I use a different type of cheese instead of Swiss?
Absolutely! While Swiss cheese gives that classic burger flavor, you can substitute with Gruyère, provolone, white cheddar, or even mozzarella. Gruyère melts beautifully and adds a nutty flavor. For a sharper taste, use aged cheddar. If you want to keep it lighter, use reduced-fat versions. The cottage cheese provides the creamy base, so the top cheese is flexible. Just note that different cheeses have different melting points; hard cheeses like Parmesan should be mixed with a meltable cheese like mozzarella to avoid a greasy texture.
How do I store leftovers and how long do they last?
Store leftover casserole in an airtight container in the refrigerator for up to 4 days. To reheat, microwave individual portions for 1-2 minutes or reheat in a 350°F oven covered with foil for about 10 minutes. The casserole also freezes well: let it cool completely, then wrap tightly in plastic wrap and aluminum foil or transfer to a freezer-safe container. Freeze for up to 3 months. Thaw overnight in the refrigerator before reheating. The texture of the cottage cheese may become slightly grainy after freezing, but the flavor remains delicious.
Can I make this casserole dairy-free?
Yes, with some substitutions. Use dairy-free cottage cheese (such as Kite Hill or Good Culture) or blend silken tofu with a tablespoon of nutritional yeast and a pinch of salt to mimic the tanginess. Replace the Swiss and mozzarella with your favorite dairy-free shredded cheese (look for brands like Daiya or Violife that melt well). Use a dairy-free butter or oil for sautéing. The flavor will be different but still delicious. Note that the protein content may vary slightly depending on the products used.
Why is my casserole watery?
A watery casserole usually results from excess moisture in the mushrooms or cottage cheese. To prevent this, ensure you cook the mushrooms until they release their liquid and it evaporates—don’t crowd the pan. If using cottage cheese, drain it in a fine-mesh sieve for 15 minutes before mixing. Also, avoid adding too much beef broth; the recipe calls for 1/2 cup, which is sufficient. If you added extra vegetables like zucchini, sauté them first to remove moisture. Finally, let the casserole rest for 5-10 minutes after baking; it will thicken as it cools.
Is this casserole low-carb or keto-friendly?
As written, this casserole is relatively low-carb with about 8g net carbs per serving (from onions, mushrooms, and a small amount from Worcestershire sauce). To make it strictly keto, use a sugar-free Worcestershire sauce or coconut aminos, and consider using full-fat cottage cheese or cream cheese instead of low-fat. You can also increase the fat by using 80/20 ground beef. Each serving would then have approximately 5-7g net carbs, fitting well within a keto diet. Serve with non-starchy vegetables like roasted broccoli or a side salad.
Can I prepare this casserole in a slow cooker or Instant Pot?
This recipe is designed for the oven to achieve a bubbly, browned cheese topping. However, you can adapt it for a slow cooker: brown the beef and mushrooms on the stovetop first, then transfer everything to the slow cooker with the broth and Worcestershire. Cook on low for 2-3 hours. In the last 15 minutes, top with the cheese mixture and cover until melted. For an Instant Pot, use the sauté function to brown the beef and mushrooms, then add broth and cook on high pressure for 5 minutes. Quick release, then stir in cottage cheese and top with Swiss cheese, using the sauté function to melt. The texture will be softer than the oven version.
What can I serve with this casserole?
This casserole is hearty enough to stand alone, but it pairs wonderfully with a simple green salad dressed with vinaigrette, steamed green beans, roasted asparagus, or a side of cauliflower rice for a low-carb meal. For a more indulgent dinner, serve with baked potatoes or crusty bread to soak up the creamy sauce. If you want to keep it macro-friendly, opt for a large portion of non-starchy vegetables. The casserole also makes a great topping for baked sweet potatoes or zucchini boats.