Turn your Blackstone griddle to medium-high heat. Allow it to get very hot for about 5 to 10 minutes. You want the surface to be lightly smoking before you begin.

Divide the ground beef into 12 equal-sized portions, roughly 2 ounces each. Roll them into loose balls. Do not overwork the meat or pack it too tightly, as this will make the burgers tough.

Slice your slider buns in half. Melt a little butter on a cooler section of the griddle and place the buns face down. Toast until golden brown and set them aside.

Apply a thin layer of oil to the hot griddle. Place the beef balls onto the surface, leaving space between them. Place a small handful of thinly shaved onions on top of each ball. Using a heavy press or a sturdy spatula, press down firmly on each ball until it is very thin and flat. Hold the pressure for about 5 seconds to ensure a good sear.

Season the smashed patties generously with salt and black pepper. Let them cook undisturbed for about 2 minutes until the edges are dark brown and crispy. Use a sharp metal spatula to scrape underneath the patty (making sure to get all that crust) and flip them over.

Immediately place a slice of American cheese on each patty. If the cheese isn’t melting fast enough, you can use a basting cover and a squirt of water to create steam, which melts the cheese instantly.

Place the bottom buns on a platter. Spread a little burger sauce on the buns. Place a cheesy patty onto each bun, top with pickles, and cover with the top bun. Serve immediately while hot.