Divide the beef into 8 balls, each about 3 oz in size. Put them in the fridge until you're ready to cook them.

Preheat the griddle to medium high (approximately 400 degrees F).

Butter the buns and toast them for 2 minutes on the griddle before setting them aside while you prepare the beef.

Then, on the griddle, melt the remaining butter. To melt it, move it around. Then, in the melted butter, place 4 of the beef balls on the griddle. Then, top each with a piece of parchment paper and firmly press down with a burger press or a large spatula to smash the beef into a thin patty, discarding the parchment paper. Season the patties with the garlic salt and pepper.

Cook the patties for 2 minutes, or until the beef juices rise to the surface and the color changes. Then, scrape under the patty to get under the caramelized parts before flipping it. After flipping, do not smash the patties again. Cook for 1 minute more, then place a piece of cheese on half of the patties to melt. Once the cheese has melted, top each of those patties with the remaining patties that do not have cheese.

Then transfer those patties to a separate platter and repeat the process until all of the patties are ready.

Then it's time to put your burgers together. On the bottom bun, layer lettuce, sliced tomatoes, and sliced red onions. Top with the tops of the hamburger buns and the double patty.

The smash burgers are then ready to eat!