Heat the beef fat in a large sauté pan over medium-high heat. Add the ground beef and season with onion powder, garlic powder, black pepper, and salt. Break it up with a wooden spoon and cook until browned.
Stir in the Worcestershire sauce and cook until the liquid has fully reduced. Turn off the heat and mix in the grated American cheese until melted and combined.
Make the Big Mac Sauce:
In a mixing bowl, combine the mayonnaise, ketchup, mustard, pickle liquid, garlic powder, and paprika. Whisk until smooth and fully combined.
Prepare the Lettuce:
Place the shredded iceberg lettuce in a bowl of iced water for 30 seconds to crisp. Drain well and set aside.
Assemble the Salad:
In a large bowl, layer the iceberg lettuce, cherry tomatoes, onions, pickles, and cooked ground beef. Drizzle the Big Mac sauce over the top and sprinkle with the grated cheese and sesame seeds.