Ground Beef and Cheese Casserole (Keto)

hamburgercasseroleketo This easy 30-minute keto cheeseburger casserole is hearty, filling and an excellent alternative to a classic cheeseburger. You can make this recipe as written and serve it with a side of veggies, or mix in veggies such as cauliflower rice or spinach and turn it into a complete meal.

2 Tbsp. extra-virgin olive oil
2 lbs extra-lean ground beef
1 medium onion, finely chopped (6 oz)
1 tsp. sea salt
¼ tsp. black pepper, freshly ground
1 Tbsp. fresh garlic, finely minced
¼ cup mayonnaise
¼ cup ketchup
1 Tbsp. mustard
1½ cup sharp cheddar, freshly shredded, divided (6 oz total)

Preheat your oven to 400°F (200°C/180°C fan, Gas Mark 6). Spray a 2 qt 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, 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 salt, pepper and garlic. Cook, stirring, for 1 more minute.

Turn the heat off. Stir in the mayonnaise, 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" below the heating element (not directly below) until the cheese is melted, 1-2 minutes. Serve immediately.

Makes 6 servings.

Cook's Notes:

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. You'll need to increase the olive oil by 1-2 Tbsp..
You can make this recipe with ground chicken or turkey thighs. It won't be the same, but it's still good. I recommend using ground chicken thighs, not chicken breast, which is too lean and dry.
You can keep the leftovers in the fridge, in an airtight container, for up to 3-4 days. Reheat gently. You can also freeze individual servings for up to three months.