Ingredients
Method
Prep
- In a small bowl, whisk together the mayonnaise, ketchup, and yellow mustard until smooth to create the secret sauce.
- Butter the cut sides of the brioche buns and toast them in a skillet over medium heat until golden brown, about 1-2 minutes.
The Smash
- Divide the cold ground chuck into 4 equal balls (about 4 oz each). Place them on a preheated cast iron skillet over high heat. Using a spatula and a sheet of parchment paper, smash each ball flat until very thin with ragged edges.
- Cook for 2 minutes without moving, until a dark crust forms. Flip the patties, immediately top each with a slice of American cheese, and stack two patties per burger. Remove from heat.
Nutrition
Notes
For the best lacy edges, keep the meat cold until it hits the pan. A cast iron skillet is essential for maximum crust; avoid non-stick pans. If you don't have parchment paper, use wax paper to prevent sticking when smashing. You can make the secret sauce ahead and refrigerate for up to a week. Serve immediately on toasted buns with sliced onion and pickles.