Keto Cheeseburger Casserole

This easy 30-minute keto cheeseburger casserole is hearty, filling, and an excellent alternative to a classic cheeseburger.

Course Main Course

Cuisine American

Prep Time 15

Cook Time 15

Total Time 30

Servings servings

Calories 458kcal

Olive oil spray for the baking dish
2 tablespoons olive oil
2 pounds extra-lean ground beef
1 medium onion finely chopped; 6 ounces
2 teaspoons Diamond Crystal kosher salt or 1 teaspoon of any other salt, including Morton kosher salt
¼ teaspoon black pepper
1 tablespoon fresh garlic minced
¼ cup mayonnaise
¼ cup unsweetened ketchup
1 tablespoon mustard
1 ½ cup cheddar sharp, shredded, divided; 6 ounces total

Preheat the oven to 400°F. Spray a 2-quart baking dish with olive oil.
Heat the olive oil in a large skillet over medium-high heat for about 2 minutes. Add the beef and the onions. Cook, stirring to break up the beef until the meat is browned and the onion is soft, for about 5 minutes.
If there are liquids at the bottom of the skillet, carefully drain the mixture and return it to the skillet. Stir in the kosher salt, black pepper, and garlic. Cook, stirring, for 1 more minute.
Turn the heat off. Stir in the mayonnaise, unsweetened ketchup, mustard, and 1 cup of shredded cheddar.
Transfer the mixture to the prepared baking dish. Sprinkle with the remaining cheese.
Bake until the cheese is melted and the casserole is heated through, for about 15 minutes. Alternatively, if your baking dish is broiler-safe, broil the casserole 6 inches below the heating element (not directly below) until the cheese is melted, 1-2 minutes. Serve immediately.

I prefer lean ground beef (85% lean) in most of my recipes, but when I cook it for a casserole, I drain the fat anyway.
If you'd like to turn this casserole into a complete meal, add 1-2 cups of uncooked riced cauliflower to the ground beef/onion and cook everything together. Increase the olive oil by 1-2 tablespoons.
You can also add two cups (about 2 ounces) of raw baby spinach leaves to the beef mixture when it's done cooking. Add the spinach right before adding the seasonings and mix it in until it wilts very slightly. Don't overcook it.
You can make this recipe with ground chicken or turkey. It won't be the same, but it's still good. I recommend using ground dark meat, as white meat is too lean.
You can keep the leftovers in an airtight container in the fridge for 3-4 days. Reheat them gently in the microwave at 50% power. You can also freeze individual servings for up to three months.