Instructions

1. 1

   Stir together the mayonnaise, ketchup, mustard, relish, and garlic powder until smooth and evenly combined. Refrigerate while preparing the burgers.

2. 2

   Place a cast-iron skillet or griddle over medium-high heat for several minutes. The surface should be hot enough that a drop of water sizzles and disappears almost immediately.

3. 3

   Lightly butter the cut sides of the buns and toast them until golden around the edges with a lightly crisp surface. Set aside.

4. 4

   Place 2 to 4 beef portions onto the hot skillet, leaving space between them. Immediately smash each portion into a thin patty using a sturdy spatula or burger press. Press firmly for about 10 seconds until the patties are very thin with uneven edges.

5. 5

   Sprinkle with salt and pepper. Let the patties cook undisturbed until the edges become dark brown and crispy and the tops begin to look slightly dry, about 2 minutes.

6. 6

   Scrape underneath each patty with a metal spatula and flip in one quick motion. Place a slice of cheese on each patty. Cook for another 30 to 60 seconds until the cheese looks glossy and melted.

7. 7

   Stack two patties together, then transfer them to the toasted buns.

8. 8

   Spread smash burger sauce on both bun halves, then add lettuce, onions, pickles, and the double cheeseburger stack. Serve immediately while the edges are still crisp.

Used in this recipe: Cast-Iron Burger Press · 12-Inch Cast-Iron Skillet · Stainless Steel Spatula (Amazon, affiliate links)