Keto Cheeseburger Casserole

Name: Keto Cheeseburger Casserole
Prep time: 15 min
Cook time: 15 min
Total time: 30 min
Ingredients: 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; 1/4 teaspoon black pepper; 1 tablespoon fresh garlic (minced); 1/4 cup mayonnaise; 1/4 cup unsweetened ketchup; 1 tablespoon mustard; 1 1/2 cup cheddar (sharp, shredded, divided; 6 ounces total)

Ingredients

You'll only need a few simple ingredients to make this recipe. The exact measurements are included in the recipe card below. Here's an overview of what you'll need:

Olive oil: My favorite oil to cook with! It's so flavorful. Other options include avocado oil and ghee.
Extra-lean ground beef: I prefer to use extra-lean ground beef (93% lean) because I drain the rendered fat anyway. However, using lean ground beef (85% lean) is OK if that's what you have. As you can see in the photo above, I sometimes use it.
Onion and garlic. Sometimes, when I'm lazy, I sub onion and garlic powders - two teaspoons of each. But it's not as good.
Kosher salt and black pepper: I use Diamond Crystal Kosher Salt.
Mayonnaise: I prefer mayonnaise made with avocado oil.
Ketchup: I use unsweetened ketchup.
Mustard: I usually like Dijon mustard. But in this recipe, yellow mustard works too.
Shredded cheddar: I like to use sharp or extra-sharp cheddar. It greatly enhances the flavor of this casserole.

Variations

The best thing about this recipe is how simple it is to make. But if you'd like to experiment a little, here are a few ideas for you:

Add crumbled cooked bacon. I love the flavor it adds.
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.
Add your favorite spices, even if they're not classic cheeseburger seasonings. Smoked paprika and chili powder are excellent in this recipe. You can add a teaspoon of each.
Sometimes, I mix sliced pickled jalapenos into the beef mixture before baking it.

Instructions

The detailed instructions for making this casserole are included in the recipe card below. Here's an overview of the steps:

You start by cooking ground beef and onion in olive oil. Drain and add seasonings: Garlic, salt, and black pepper.

Cooking ground beef and onions in a skillet.

The ground beef is cooked in the skillet.

Off heat, stir in condiments: Mayo, ketchup, and mustard. Then, stir in shredded cheese.

Adding condiments to the beef mixture in the skillet.

Adding shredded cheese to the beef mixture in the skillet.

The last step is to transfer the mixture to a greased baking dish and sprinkle it with more cheese. Bake the casserole for about 15 minutes at 400°F, then serve!

Cheeseburger casserole in a baking dish.

Expert Tip

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 mixture and cook everything together. If you do, increase the olive oil by 1-2 tablespoons.

Recipe FAQs

What type of beef do you use in a cheeseburger casserole?

I use extra lean ground beef (93% lean). 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.

Can I add vegetables?

Absolutely! One option mentioned above is to add riced cauliflower
to the beef/onion mixture.

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.

Can you make a casserole without a starchy ingredient?

Yes! A classic casserole contains protein (meat, poultry), starch (rice, potatoes), vegetables, sauce, and cheese.

But one of the best things about casseroles is that they are flexible and forgiving, so you can adapt them to your needs and the ingredients you have on hand. Made as written, this casserole contains just protein, sauce, and cheese and is delicious.

Storing Leftovers

You can keep the leftovers in the fridge, in an airtight container, for 3-4 days. Reheat them gently in the microwave at 50% power. You can also freeze individual servings of this cheeseburger casserole for up to three months.