Add the mayonnaise, ketchup, and pickle relish to a small bowl; stir well to combine. Set aside or refrigerate until ready to use.
Cook the ground beef in a large skillet over medium-high heat. Break up the ground beef as it browns. When the ground beef is no longer pink, remove the pan from the heat and drain the excess grease.
Add the onion powder, garlic powder, and salt to the skillet with the beef. Stir the ingredients well to combine.
Place the casserole mixture into a greased 9" x 13" baking dish and use a flat spatula or the back of large spoon to smooth it out. *If you used an oven-safe skillet, you can assemble the casserole in the skillet instead.Sprinkle the diced onions evenly over the top, then cover with a layer of American cheese slices.
Add a single layer of tater tots over the sliced cheese, then sprinkle the shredded cheese on top of the tater tots.
Bake at 400ºF for 25-30 minutes, until the cheese melts and is golden brown.
Remove the casserole from the oven and let it cool for 5 minutes. Sprinkle the shredded lettuce and diced tomatoes evenly over the top of the tater tot casserole.
Garnish with a drizzle of special sauce just before serving.
Notes
Never pour hot grease down a drain. Pour it into a trash can, mason jar, or any other heat-safe container. This will prevent it from clogging up your kitchen drain pipes!
Recipe Variations:In addition to the substitutions shown above, here are some other alterations you can make to your cheeseburger tater tot casserole:
Use a different ground protein, such as chicken or turkey.
Flavor the ground beef with barbecue sauce, Worcestershire sauce, or some Dijon mustard. Whatever your secret burger ingredient is, don’t hesitate to add it to this recipe!
Crumbled bacon is a fantastic add-in for tons of savory flavor. Add it to the ground beef, or crumble it over the top of the casserole when you add the cheese.
Soft avocado and sour cream are two popular toppings that add creaminess to this hamburger potato casserole. Try it out!
Storing Instructions:
Leftovers can be refrigerated for up to 4 days. The potatoes will turn soggier with each day. So, if possible, reheat in the oven or air fryer within a couple of days.
This hamburger potato casserole can also be frozen for up to 2 months. Thaw it in the fridge overnight before reheating.
Reheat in a 350º F. oven until the dish is warm all the way through. You may need to add a few minutes to the reheating time if you're reheating it from frozen.
You can also reheat individual servings in the microwave. Just place the desired amount in a microwave-safe dish and heat it for 1-2 minutes, or until it's hot.
Reheat the leftover casserole at 400°F., for 5-7 minutes, or until it is warm all the way through.