Smash Burger with Caramelized Onions & Secret Sauce

Ingredients

Burgers

• 1.5 lb ground beef (80/20)
• 1 large onion, thinly sliced
• 4 brioche burger buns, toasted
• 4 slices American or cheddar cheese
• Kosher salt and freshly ground black pepper
• 1 tbsp neutral oil or butter

Secret Sauce

• 1/3 cup mayonnaise
• 2 tbsp ketchup
• 1 tbsp yellow mustard
• 2 tsp sweet pickle relish
• 1 tsp Worcestershire sauce
• 1/2 tsp smoked paprika
• 1/2 tsp garlic powder
• 1/4 tsp onion powder
• 1–2 tsp pickle juice or lemon juice, to taste
• Pinch of cayenne or hot sauce, optional

Toppings

• Dill pickle chips
• Shredded iceberg lettuce
• Tomato slices (optional)

Instructions

1. Make the sauce: Whisk mayonnaise, ketchup, mustard, relish, Worcestershire, paprika, garlic powder, onion powder, and pickle or lemon juice. Adjust salt, pepper, and heat. Refrigerate.
2. Caramelize the onions: Heat skillet over medium with oil or butter. Add onions and a pinch of salt. Cook, stirring, until deep golden and jammy, 10–12 minutes. Lower heat if browning too fast. Set aside.
3. Portion the beef: Divide into 8 loose balls (about 3 oz each). Do not compact. Lightly season with salt and pepper.
4. Toast buns: Lightly toast buns on the skillet until golden; set aside.
5. Smash and sear: Raise heat to medium-high. Place 2–3 beef balls on the hot skillet. Immediately smash to about 1/4 inch. Season. Cook 1–2 minutes until edges are lacy and browned.
6. Flip and cheese: Flip, top with cheese, and cook 30–60 seconds until cheese melts and centers are medium to medium-well. Repeat with remaining patties.
7. Assemble: Spread secret sauce on buns. Add pickles and lettuce to bottom bun. Stack two patties, spoon on warm caramelized onions, add tomato if using, and cap.