Heat the griddle, grill pan or cast iron pan over high heat until it is very hot (smoking hot). Butter the cut-side of the buns with the butter. Toast the buns, cut side down on the grill until lightly golden brown, about 10 seconds. Remove the buns to a flat surface, butter-side up.
Divide the beef into 4 equal portions (3.5 ounces each) and gently form into balls, do not form patties. Season liberally with salt and pepper. Place the balls of beef on the hot surface (in batches, if needed) making sure to leave at least 4 inches between each burger. Let the beef cook for 20 seconds (without touching).
Place a piece of parchment paper on top and using a cast iron burger press or heavy duty metal spatula, press firmly on the burger, smashing it into a flattened burger.
Let cook until the bottom is golden brown, about 60 seconds depending on the heat of your grill. Flip the burger over and continue cooking until bottom is golden brown, about 60 seconds longer.
Top the burger with a slice of cheese and cover with a dome, squirting a bit of water onto the cooking surface first (to create steam once you cover it) and let cook for 10 seconds longer or until the cheese is completely melted.
Remove the burgers to a platter or baking sheet and let rest for a few minutes while you assemble the toppings.
Spread a heaping tablespoon of the Kalamazoo Burger Sauce on the top and bottom of each bun. Divide the pickles among the bottom bun and top with a burger and then lettuce, onion and, finally, cap off with the top bun. Enjoy!
