Smash Burgers with Mustard Smash Sauce Recipe
These Smash Burgers with Mustard Smash Sauce are crispy, juicy, and full of flavor. Made with simple ingredients, the beef patties are smashed thin and cooked in a hot skillet for a perfect crust, then topped with melted American cheese and a tangy mustard-based sauce. Served on toasted brioche buns with fresh lettuce, pickles, and onions, this recipe delivers a classic diner-style burger experience in just 15 minutes.
- Prep Time: 5 minutes
- Cook Time: 10 minutes
- Total Time: 15 minutes
- Yield: 4 servings
- Category: Main Dish
- Method: Frying
- Cuisine: American
Ingredients
Burger Sauce
- ¼ cup whole-grain mustard
- ¼ cup prepared yellow mustard
- ¼ cup olive oil mayonnaise
Burgers
- 1 pound (80/20) ground beef
- Morton kosher salt, to taste
- 4 brioche buns, split
- 1 medium yellow onion, very thinly sliced
- ½ head iceberg lettuce, leaves separated
- 3 large kosher dill pickles, thinly sliced, plus extra for serving
- 4 slices American cheese (such as Kraft Singles)
Instructions
- Prepare the Burger Sauce: In a small bowl, combine the whole-grain mustard, yellow mustard, and olive oil mayonnaise. Mix thoroughly until smooth and set aside for serving.
- Form the Beef Balls: Divide the ground beef into four equal portions (about 4 ounces each) and gently roll each into a ball. Arrange them on a plate or small baking sheet and set aside.
- Heat the Skillet: Place a large (12-inch) cast-iron, stainless steel, or carbon steel skillet over medium-high heat. Allow it to become very hot and start to smoke, which should take about 5 minutes. This high heat is key to creating a crispy crust on the burgers.
- Toast the Buns: Place half of the split brioche buns cut side down in the hot skillet. Toast them until lightly golden, approximately 1 minute. Remove and repeat with the remaining buns.
- Increase Heat: Turn the heat up to high to prepare for cooking the patties.
- Cook the Patties: Add two beef balls to the hot skillet. Season them generously with kosher salt. Using a heavy-duty spatula and, for extra leverage, a potato masher on top of it, press each beef ball down firmly until it is very thin, about ½ inch thick. Let cook without moving for about 1½ minutes, allowing a crisp, brown crust to form on the bottom.
- Add Onions and Flip: Press a few slices of the thinly sliced onion into each patty using the spatula. Then, carefully scrape under the patty and flip it over.
- Top with Cheese and Finish Cooking: Immediately place a slice of American cheese over each patty. Continue cooking for 30 to 60 seconds until the cheese melts and the onions on the bottom side are golden and griddled. Remove the patties from the skillet and set aside.
- Assemble the Burgers: Spread about 1 tablespoon of the prepared mustard smash sauce onto the cut side of each toasted bun top and bottom. Place a few pickle slices on the bottom buns, then add the burger patty. Top with a few slices of raw onion and a couple of folded iceberg lettuce leaves. Crown with the top buns.
- Repeat Cooking: Wipe out the skillet with paper towels to remove any browned bits and excess fat. Repeat the smashing and cooking process with the remaining beef balls, onions, and cheese for the remaining burgers.
- Serve: Serve the completed smash burgers immediately with extra pickle spears on the side.
Notes
- Using a very hot skillet and smashing the beef thinly is crucial to develop the signature crispy crust on the burgers.
- Pressing onions into the patties adds sweetness and an extra flavor dimension.
- Feel free to substitute American cheese with your preferred melting cheese like cheddar or pepper jack.
- For best results, use 80/20 ground beef for optimal fat content to keep the patties juicy.
- Serve immediately after cooking to enjoy the melty cheese and crispy edges.
