Prepare burger seasoning by combining the salt, black pepper, onion salt, and garlic salt together in a small bowl.
Prepare the garlic butter by melting together the butter and adding the two teaspoons of minced garlic in a small saucepan. Heat melted butter for 3 to 5 minutes or until the garlic butter becomes fragrant.
Brush the garlic butter onto the buns, and place the buns on the skillet to toast. Toast the buns long enough so the bread begins to brown.
Brush a small amount of the butter on top of the ground beef and then sprinkle some garlic salt on top.
Heat the grill or skillet to medium-high heat.
Place the ground beef balls on the heated surface and use a spatula to press the burgers into thin patties.
Season patties with the salt mixture.
When the burgers have cooked on one side, flip them over and add a slice of cheese to each patty.
Stack half of the burger patties on top of the other. Place the patties onto the buns. Dress the burgers as you desire.
Recipe Tips
Work in batches. Crowding the pan drops the surface temperature and the patties steam instead of browning. Two or three at a time is plenty in a 12-inch skillet.
The parchment square is what keeps the beef from lifting off with the spatula. A sheet of deli paper or foil works the same way.
Do not scrape the browned bits out of the pan between batches. Those are flavor, and they season the next round.
You will have garlic butter left over. Refrigerate it and use it on bread, vegetables, or the next batch of burgers. If you would rather not have extra, halve the butter and garlic.
If you want the cheese fully melted without overcooking the beef, add a tablespoon of water to the pan after flipping and cover it for 20 seconds. The steam does the work.
A grill will not give you the same crust unless you put a flat griddle plate or cast iron pan on the grates. Grill bars mean less surface contact, which is the opposite of what a smash burger needs.