Make the sauce first, whisking all the ingredients together in a bowl. Set aside.
Divide meat into 2 ounce meatballs. Dust well with garlic powder. Sprinkle lightly with white pepper. Right before placing them in the skillet season well with kosher salt.
Heat skillet on high heat. Once it's very hot, place 2 patties (or more if your skillet is large enough) into skillet and smash down immediately. Cook for 1 minute and 30 seconds. Flip patty and top with American cheese. Once the cheese has melted (15-30 seconds) transfer patties to plate. Finish the rest of the patties.
Serve on toasted buns with tomato, lettuce and slathered in sauce.
Recipe by Talia Bunting at https://www.taliabunting.com/double-patty-burger/