In a large skillet over medium high heat, add the ground beef, diced onions and All Purpose Seasoning. Cook and crumble the beef with a spoon for 6-7 minutes or until the beef is no longer pink. Drain off any excess fat.
Meanwhile, make the sauce by adding all of the ingredients to a bowl and whisking until combined. Set aside.
Once the beef is cooked and drained, reserve ⅓ cup of the sauce and set aside. Add the remaining Big Mac Sauce to the pan and stir until combined.
Transfer the beef mixture to a greased 13x9 baking dish and spread it into an even layer.
Add the shredded cheese in a single layer on top of the beef.
Arrange the tater tots in a single layer on top of the cheese.
Bake for 40-45 minutes or until the tater tots are golden and crispy.
Remove the casserole from the oven and top with shredded lettuce, chopped tomatoes and chopped pickles. Drizzle with the reserved sauce before serving.
Christina's Notes
Drain Grease: Drain any extra grease from the ground beef to prevent greasy casserole and soggy tater tots.
Season: Don't be shy with the seasoning. Use a little garlic powder, onion powder, paprika, and salt and pepper.
Pickles: Chopped pickles are crucial for getting the burger flavor.
Let Rest: Let the casserole sit for 5-10 minutes before trying to scoop. This lets the cheese set slightly, making it easier to serve.