In a small bowl, mix together the mayo, ketchup, mustard, yellow mustard, Worcestershire sauce, garlic powder, onion powder, Cajun seasoning, and minced garlic until smooth. Add a pinch of salt if needed. Set aside. 1/2 cup Mayo1/4 cup Ketchup1 tbsp Yellow Mustard2 tsp Worcestershire Sauce1 tsp Garlic Powder1 tsp Onion Powder1 tsp Cajun Seasoning 1 Garlic clove
Gather your cheese, onions, buns, and any additional toppings before you start cooking. Smash burgers cook fast, so you want everything ready to go. 8 slices Sharp Cheddar Cheese1 Yellow Onion4 Brioche Burger Buns
Heat a flat griddle or large cast-iron skillet over medium heat. Add butter, then place the buns cut-side down. Toast for 2-3 minutes, until golden brown. Remove from the griddle and set aside. 2 tbsp Salted Butter4 Brioche Burger Buns
Add the sliced onions to the griddle and cook for about 5 minutes, until softened and lightly browned. Remove from the griddle and set aside. 1 Yellow Onion
Remove the ground beef from the fridge. Weigh out 3-ounce portions and gently roll each portion into a loose ball. Place onto a piece of parchment paper. Do not pack the meat too tightly. 2 lbs Ground Beef
Increase the heat to medium-high and let the griddle get very hot. Add a drizzle of vegetable oil (or any high smoke point oil), then place 2 beef balls onto the griddle. Let them cook for about 30 seconds per side before smashing.
Place a small piece of parchment paper over each beef ball, then press firmly with a burger press or sturdy metal spatula until thin and flat. Remove the parchment paper and sprinkle the burgers with a little kosher salt, black pepper, and a ash of garlic powder. Let the patties cook for 1-2 minutes, until the edges are crispy and browned. Kosher SaltBlack PepperGarlic Powder
Use a sturdy metal spatula to scrape underneath each patty, making sure to lift up the crispy crust. Flip the patties, then immediately add cheese. Cook for about 1 minute, until the cheese is melted.
Assemble the burgers. Spread burger sauce onto the toasted buns. Add the 2 smash burger patties per burger then top with cooked onions, your favorite toppings, and more sauce. Add the top bun and serve immediately.
Notes
Smash once, then let it cook. Press the patty firmly, then leave it alone so the edges can crisp up. Pressing the burgers more than once can press out all of the juices, making the patties dry.
Scrape, don’t just flip. Use a sturdy metal spatula to scrape underneath the patty so you don’t leave that crispy crust behind.
Add cheese right after flipping. Smash burgers cook quickly, so add the cheese as soon as you flip the patties so it melts while the second side finishes cooking.