Form 2 1/2 inch thick patties with beef, using a light touch. Make a small dimple in the center of the patties. Sprinkle with truffle salt on both sides.
Cook bacon in cast iron skillet until medium crisp. Remove bacon and reserve 2 Tbsp. bacon drippings.
Heat bacon drippings over high heat. Cook patties over high heat, not moving, for 2 minutes. Flip and cook over medium heat 3-4 minutes, without moving or smashing down with a spatula. Leave in pan, off heat, covered, while you fry duck eggs.
Over high heat, fry duck eggs in 2 Tbps butter
Assemble burgers: On bottom of bun place a handful of pickles. Place patty on top of pickles, followed by bacon, avocado, fried egg and tomato. Place top bun on top and dig in!