Preheat the oven to 400°F. Lightly spray a 9x13-inch baking dish with nonstick cooking spray. Set aside.
In a medium mixing bowl, whisk together all of the special sauce ingredients until smooth and creamy. Set the sauce aside for later.
1 cup mayonnaise, 1/2 cup thousand island dressing, 2 tablespoons finely diced dill pickles, 1 tablespoon dill pickle juice, 1 tablespoon yellow mustard, 1 teaspoon granulated sugar, 1 teaspoon white vinegar, ½ teaspoon paprika
In a large skillet, over medium-high heat, heat the olive oil. Add the ground beef and finely diced onion, and cook and crumble the beef until it's no longer pink. Drain excess grease from the skillet.
1 tablespoon olive oil, 1 pound lean ground beef, 1/2 cup finely diced yellow onion
Add the onion powder, garlic powder, kosher salt, and black pepper into the cooked ground beef, then stir and cook for 1 minute to incorporate and activate the seasonings.
1 teaspoon onion powder, 1 teaspoon garlic powder, ½ teaspoon kosher salt, ¼ teaspoon black pepper
Stir 1/2 cup special sauce into the ground beef mixture. Gently stir to coat the meat. Spread this into an even layer inside the prepare baking dish.
Lay the slices of American cheese over top the beef layer. You may have to cut a few pieces into strips to fit your dish and to cover the meat layer completely.
8 slices american cheese
Evenly arrange the frozen tater tots in a neat, single layer over top the cheese. Make sure to cover the surface evenly.
1 bag (32 oz) frozen tater tots
Bake uncovered for 35 minutes or until the tater tots of crispy golden brown, the cheese underneath is fully melted, and bubbling around the edges.
Remove the casserole from the oven and let it rest for 5 minutes.
Drizzle a small amount of the remaining special sauce over top of the tater tots. Then sprinkle the shredded iceberg lettuce over it, then the pickles, then the sesame seeds, and finish by drizzling the remaining special sauce over top of everything.*Serve any remaining sauce for dipping or as an extra garnish that people can use if they want it saucier. Another option is to serve the toppings all on the side and then everyone can top their own serving how they want. 1 cup shredded iceberg lettuce, finely chopped dill pickles OR dill pickle slices, white sesame seeds