Mustard-Fried Smash Burger with Secret Sauce Step-by-step instructions

Before you start

Start by dicing the yellow onions into small, uniform pieces to ensure they cook evenly. Measure out all your sauce ingredients and prepare the patties by gently forming them into balls, handling the meat as little as possible to keep it tender.

Ensure your workspace is clean, your spatula is clean and sturdy, and your pan is ready on the stove. Having all components within arm's reach is essential, as the actual cooking process is extremely fast and requires your full attention once the heat is turned on.

Instructions

Prep and Sauce Development

1. 1Prepare the Secret Sauce
   In a small mixing bowl, whisk together the mayonnaise, ketchup, sweet pickle relish, and white vinegar until smooth and well combined. Set the sauce aside to allow the flavors to meld while preparing the rest of the ingredients.
   Look for The sauce should have a uniform, creamy consistency.
   Tip Make this sauce at least 30 minutes in advance for the best flavor.
2. 2Caramelize the Onions
   Place the diced yellow onion in a skillet over medium heat. Sauté the onions until they are soft, translucent, and golden brown. Remove them from the heat and keep warm until assembly.
   Look for Onions should be deeply caramelized and fragrant.
   Tip Add a pinch of salt to draw out moisture and speed up the process.

The sauce should be uniform and smooth, with the relish distributed evenly throughout. The onions should be soft and golden, not burnt. Ensure the sauce is chilled or set aside at room temperature before you begin the high-heat searing process, as you will not have time to multitask once the beef hits the pan.

Searing and Melding

3. 3Sear the Beef Patties
   Heat a heavy steel pan or flat top griddle to 450°F (232°C). Place the ground beef patties onto the hot surface and smash them thin with a heavy spatula. Immediately squirt the yellow mustard onto the raw top side of the patties.
   Look for The beef should sizzle loudly upon contact with the hot surface.
   Safe temperature 160°F (71°C) internal temperature (ground meat)
   Tip Ensure the pan is smoking hot before adding the meat for the best sear.
4. 4Flip and Melt Cheese
   Once a dark, crispy crust has formed on the bottom, flip the patties over. Top each patty with a slice of American cheese and cook until the cheese is melted and the internal temperature reaches 160°F (71°C).
   Look for Cheese should be bubbling and fully melted over the edges of the patty.
   Safe temperature 160°F (71°C) internal temperature (ground meat)
   Tip Cover the pan with a lid for 30 seconds to help the cheese melt faster.

The patties should have a dark, charred crust on the bottom side. The mustard should be bubbly and integrated into the beef. When you flip, the patties should release easily from the pan.

Once the cheese is added, it should melt within thirty seconds. The kitchen should smell intensely of searing beef and savory mustard.

Final Assembly

5. 5Assemble the Burgers
   Toast the sponge dough buns until golden. Spread the prepared secret sauce on both sides of the bun. Place the cheeseburger patties on the bottom bun, top with caramelized onions and dill pickles, then finish with the top bun.
   Look for The bun should be lightly toasted and warm to the touch.
   Tip Assemble immediately to keep the crust crispy.

The buns must be warm and slightly toasted to prevent them from absorbing too much sauce and becoming soft. Layer the ingredients carefully so the burger holds its shape. The final result should be a tight, uniform stack where every bite contains a mix of the crusty beef, creamy sauce, and sweet onion.

Common mistakes

One common mistake is overcrowding the pan, which prevents the beef from searing properly and causes it to steam instead. Cook only one or two patties at a time to maintain the necessary high heat.

Another frequent error is moving or flipping the meat too early; wait until a deep, dark crust has developed before attempting to flip. Finally, ensure the pan is actually at the required temperature before adding the meat; a cold pan will lead to greasy, pale patties.

How to tell it’s done

The patties are perfectly done when they reach an internal temperature of 160°F (71°C). Visually, the edges should be dark brown and crispy, while the cheese is completely melted and slightly draped over the sides of the patty.

The center should still be moist. Using a meat thermometer is the most reliable way to ensure safety, as the thin nature of the patty makes it difficult to judge doneness by color alone. Avoid overcooking, as this will result in a loss of texture.

• Ground meat: 160°F (71°C) in the thickest part