Place the thawed beef into a bowl. Add kosher salt and pepper. Using your hands, work in the salt and pepper. Do not overmix the beef.
Using a ⅓ cup measuring cup, or an ice cream scoop, divide the beef into 12 even balls of meat. Do not compress the meat like a meatball. Keep the meat as loose as possible so it will be easier to smash.
Preheat the Blackstone griddle to medium heat. Add a tablespoon of avocado oil, and using your large metal spatula, spread the oil on the flat top griddle.
Place the ball of meat on the oiled griddle. Top with a piece of parchment paper and firmly press the ball of meat down. Lift the press and press again in a different direction. Peel up the parchment paper and set it aside for the next smashburger.
Cook the thin beef patty for two minutes. Flip the patty with a metal spatula, and flip it to a different spot on the griddle.
Cook the other side of the patty for two minutes. Add a piece of deli American cheese to the top of the burger.
Remove the smashburger from the griddle, place it on a platter, and set aside.
If using a hamburger bun, butter both sides of the bun and toast. This will take less than two minutes. Watch closely and remove when golden brown.
If using a lettuce wrap, wash and pat dry your lettuce and set aside until ready to build your lettuce wrap smash burger.
Notes
Note 1: Use a 90/10 mixture for flavor. It is my favorite for this recipe. However, an 80/100 will also work. It will just be greasier. Note 2: For the best cheese option, choose American cheese that comes from the deli counter. Nutrition facts do not include any burger toppings, buns, or sauces.