Keto In-N-Out Burger Casserole – A Low-Carb Twist on a Fast-Food Favorite
If you love a classic In-N-Out burger but want to keep it low-carb, this casserole hits the spot. It has all the flavors you crave—juicy beef, melty cheese, tangy pickles, and a creamy special sauce—without the bun. It’s simple enough for a weeknight and satisfying enough for a weekend crowd.
Best of all, it’s one pan, easy to prep, and reheats beautifully. This is comfort food that actually fits your goals.
Ingredients
Method
- Preheat the oven to 375°F (190°C). Grease a 9x13-inch casserole dish.
- Make the special sauce: In a bowl, whisk together mayonnaise, sugar-free ketchup, mustard, pickle juice, vinegar, and sweetener. Adjust salt and pepper to taste. Set aside.
- Cook the beef: Heat oil in a large skillet over medium-high. Add the onion (if using) and cook 3–4 minutes until softened. Add garlic and cook 30 seconds.
- Add the ground beef. Season with salt, pepper, smoked paprika, onion powder, and garlic powder. Cook, breaking up the meat, until browned. Drain excess grease.
- Stir in 2–3 tablespoons of the special sauce and half the chopped dill pickles. This flavors the beef and keeps it moist.
- Assemble layer 1: Spread the beef mixture evenly in the casserole dish. Top with the American cheese slices for that classic fast-food melt.
- Assemble layer 2: Sprinkle the shredded cheddar over the American cheese.
- Bake for 10–12 minutes, until the cheese is melted and bubbling around the edges.
- Finish with fresh toppings: Let the casserole rest 5 minutes. Top with shredded lettuce, remaining pickles, and diced tomatoes (if using).
- Drizzle generously with the remaining special sauce. Slice and serve warm.
What Makes This Recipe So Good
- All the flavor, fewer carbs: You’ll get the taste of a “protein-style” In-N-Out burger, layered into a cozy, cheesy bake.
- Family-friendly: Even non-keto eaters enjoy it. It’s familiar, hearty, and customizable.
- Meal-prep ready: Makes great leftovers and freezes well, so you can cook once and enjoy all week.
- Simple ingredients: Nothing fancy—just ground beef, cheese, low-carb veggies, and a quick homemade sauce.
- Satisfying and filling: High in protein and healthy fats to keep you full and energized.
Shopping List
- Ground beef (85–90% lean), 2 pounds
- Yellow onion, 1 medium (or half for fewer carbs)
- Garlic, 2 cloves
- Romaine or iceberg lettuce, 2 cups shredded (for topping)
- Dill pickles, 1/2 cup chopped
- Tomatoes, 1 cup diced (optional, for topping)
- Shredded cheddar, 2 cups
- American cheese slices, 4–6 slices (optional but classic)
- Avocado oil or olive oil, 1 tablespoon
- Salt and black pepper
- Smoked paprika, 1 teaspoon
- Onion powder, 1 teaspoon
- Garlic powder, 1/2 teaspoon
- Yellow mustard, 2 tablespoons
- Sugar-free ketchup, 1/3 cup
- Mayonnaise, 1/2 cup
- Dill pickle juice, 1 tablespoon
- White vinegar, 1 teaspoon
- Erythritol or allulose, 1/2 teaspoon (optional, for sauce balance)
Instructions
- Preheat the oven to 375°F (190°C).
Grease a 9×13-inch casserole dish.
- Make the special sauce: In a bowl, whisk together mayonnaise, sugar-free ketchup, mustard, pickle juice, vinegar, and sweetener. Adjust salt and pepper to taste. Set aside.
- Cook the beef: Heat oil in a large skillet over medium-high.
Add the onion (if using) and cook 3–4 minutes until softened. Add garlic and cook 30 seconds.
- Add the ground beef. Season with salt, pepper, smoked paprika, onion powder, and garlic powder.
Cook, breaking up the meat, until browned. Drain excess grease.
- Stir in 2–3 tablespoons of the special sauce and half the chopped dill pickles. This flavors the beef and keeps it moist.
- Assemble layer 1: Spread the beef mixture evenly in the casserole dish.
Top with the American cheese slices for that classic fast-food melt.
- Assemble layer 2: Sprinkle the shredded cheddar over the American cheese.
- Bake for 10–12 minutes, until the cheese is melted and bubbling around the edges.
- Finish with fresh toppings: Let the casserole rest 5 minutes. Top with shredded lettuce, remaining pickles, and diced tomatoes (if using).
- Drizzle generously with the remaining special sauce. Slice and serve warm.
Storage Instructions
- Refrigerator: Store the casserole (without the fresh lettuce and tomatoes) in an airtight container for up to 4 days.
Add fresh toppings just before serving.
- Freezer: Freeze the baked beef-and-cheese base (no fresh toppings) for up to 2 months. Thaw in the fridge overnight.
- Reheat: Warm in a 325°F oven for 15–20 minutes or microwave in 45-second bursts until hot. Add fresh toppings and sauce after reheating.
Health Benefits
- Low-carb, high satiety: Skipping the bun and using low-sugar sauce keeps net carbs low while protein and fat increase fullness.
- Balanced keto macros: Ground beef and cheese deliver protein and fats that support steady energy and fewer cravings.
- Nutrient-dense add-ins: Lettuce, pickles, and tomatoes add fiber, potassium, and antioxidants without excess carbs.
- Customizable fats: Use higher-fat beef or add avocado to align with your macro targets.
Common Mistakes to Avoid
- Using a sugary sauce: Standard ketchup adds hidden carbs.
Choose a sugar-free ketchup to keep it keto.
- Skipping the drain: Not draining beef can make the casserole greasy. Drain well before layering.
- Adding lettuce before baking: Fresh toppings should go on after baking to keep them crisp.
- Overbaking: The meat is already cooked. Bake just until the cheese melts to prevent dryness.
- Underseasoning: Burgers rely on bold flavors.
Taste the beef and sauce and adjust salt, pepper, and mustard as needed.
Recipe Variations
- Animal-Style Inspired: Caramelize the onions slowly in butter until deep golden and sweet, then layer over the beef before baking.
- Bunless Double-Double: Use two thinner beef layers with cheese between them for extra heft.
- Spicy Kick: Add sliced jalapeños, a pinch of cayenne, or use pepper jack instead of cheddar.
- Protein Swap: Try ground turkey or chicken. Add a tablespoon of olive oil to keep it juicy.
- Loaded Bacon: Crumble crispy bacon into the beef and sprinkle some on top after baking.
- Dill Pickle Lovers: Stir in extra chopped pickles and a splash more pickle juice for punchier tang.
- Dairy-Light: Reduce cheese by half and add avocado slices after baking for creamy richness with fewer dairy calories.
FAQ
How many carbs are in a serving?
Carbs vary with toppings and sauces, but a typical serving lands around 4–6g net carbs when using sugar-free ketchup, minimal onion, and no tomatoes. Track ingredients for precise macros.
Can I make this ahead?
Yes.
Assemble the beef-and-cheese layers, cover, and refrigerate for up to 24 hours. Bake when ready, then add fresh toppings and sauce right before serving.
What’s the best ground beef to use?
Use 85–90% lean for a balance of flavor and less grease. If using fattier beef, drain well.
If using leaner beef, add a tablespoon of olive oil or a splash of cream for moisture.
Do I need both cheddar and American cheese?
No, but the combo gives you classic burger flavor and great melt. If you prefer, use all cheddar or swap in pepper jack, Colby, or provolone.
Is the sauce really necessary?
It’s the signature flavor. The sauce ties everything together with tang and creaminess.
If you’re pressed for time, mix mayo, mustard, and sugar-free ketchup and call it good.
Can I make it without onions?
Absolutely. Skip the onion or use just a few tablespoons of finely minced onion to keep carbs even lower.
How do I keep the lettuce crisp?
Add lettuce only after baking and resting. Pat it dry with a paper towel so it doesn’t wilt from residual moisture.
What if I don’t have sugar-free ketchup?
Use tomato paste thinned with a little water, sweetener, and vinegar to taste.
Start with 2 tablespoons paste, 1 tablespoon water, a pinch of sweetener, and 1/2 teaspoon vinegar.
Wrapping Up
This Keto In-N-Out Burger Casserole brings fast-food nostalgia to your table without the carbs or the drive-thru. It’s bold, cheesy, and easy to customize for your crew. Keep a jar of the special sauce on hand, and you’ll have a quick, crowd-pleasing dinner ready any night of the week.
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