Prepare the Beef Mixture

1. Heat a large skillet over medium heat and add 1 tablespoon oil (optional).
2. Add ground beef and cook until browned, breaking it apart with a spoon (about 5-7 minutes).
3. Stir in salt, pepper, garlic powder, and onion powder.
4. Add diced onions and cook for another 3-4 minutes until softened.
5. Drain excess grease and remove from heat.

2. Assemble the Casserole

1. Preheat oven to 375°F (190°C).
2. Grease a 9×13-inch baking dish with nonstick spray.
3. Spread cooked beef mixture evenly in the baking dish.
4. Sprinkle 1½ cups shredded cheese over the beef.
5. Add a layer of chopped pickles for tangy flavor.
6. Arrange tater tots evenly on top in a single layer.

3. Make the Big Mac Sauce

1. In a bowl, whisk together mayonnaise, ketchup, mustard, vinegar, pickle relish, paprika, and onion powder.
2. Taste and adjust seasonings if needed.
3. Reserve half the sauce for serving.

4. Bake the Casserole

1. Place the dish in the preheated oven and bake uncovered for 30-35 minutes, or until the tater tots are golden brown and crispy.
2. Remove from oven and drizzle half of the Big Mac sauce over the top.
3. Sprinkle with remaining ½ cup cheese and sesame seeds (optional).
4. Return to the oven for an additional 5 minutes, until cheese melts.

5. Serve & Garnish

1. Let the casserole cool for 5 minutes before serving.
2. Garnish with shredded lettuce for a fresh crunch.
3. Serve with extra Big Mac sauce on the side.
4. Enjoy your homemade Big Mac Casserole with a fork—or serve it burger-style on toasted buns!