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Keto In-N-Out Burger Casserole - A Low-Carb Twist on a Fast-Food Favorite

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Prep Time 15 minutes
Cook Time 30 minutes
Total Time 45 minutes
Servings: 6 servings
Ingredients Method

Ingredients
  

  • 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)

Method
 

  1. Preheat the oven to 375°F (190°C). Grease a 9x13-inch casserole dish.
  2. 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.
  3. 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.
  4. 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.
  5. Stir in 2–3 tablespoons of the special sauce and half the chopped dill pickles. This flavors the beef and keeps it moist.
  6. Assemble layer 1: Spread the beef mixture evenly in the casserole dish. Top with the American cheese slices for that classic fast-food melt.
  7. Assemble layer 2: Sprinkle the shredded cheddar over the American cheese.
  8. Bake for 10–12 minutes, until the cheese is melted and bubbling around the edges.
  9. Finish with fresh toppings: Let the casserole rest 5 minutes. Top with shredded lettuce, remaining pickles, and diced tomatoes (if using).
  10. Drizzle generously with the remaining special sauce. Slice and serve warm.