Prep: Remove the minced beef from the fridge and leave it to come up to room temperature for 1 hour before cooking.
Fixings: Prepare all of your burger fixings before starting cooking.
Heat: Heat two large flat griddle pans or a flat-top BBQ to high heat.
Shape: Divide the meat into 8 equal portions and roll each portion into a ball, pressing the fibers of the meat together.
Season: Season the top of each ball with salt and pepper. Add the balls to the cooking surface, seasoning side down, making sure you leave enough space to squash the burgers down.
Smash: Place a piece of parchment paper on top of each meatball and squash the burgers down using a burger press or double spatulas until thin.
Flip: Remove the parchment paper, season the other side, and allow to cook for 2 minutes to build up a crust. Use a spatula or scraper with a thin edge to flip the burgers.
Melt: Add a slice of cheese to each burger. Cover with a cloche for 30 seconds to help melt the cheese.
Double: Double up the burgers (so you now have four double cheeseburgers) and remove them from the heat. Let them rest while you prepare the buns.
Build: Build the burgers starting with the bottom bun, then lettuce, tomato, double smashed burger, burger sauce, diced onion, and pickles. Top with the other half of the bun and serve.