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Smash Burger with Caramelized Onions and Special Sauce

Juicy smash burgers with crispy edges, melted American cheese, sweet mayonnaise-caramelized onions, and a creamy special sauce. Fast, messy, and packed with flavor.
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Prep Time 10 minutes
Cook Time 20 minutes
Total Time 30 minutes
Servings 4
Calories 650 kcal

Equipment

  • 1 | Cast-iron griddle or skillet |
  • 1 | Metal spatula | for smashing
  • 1 | Wooden spoon | for stirring onions
  • 1 | Mixing bowl |
  • 1 | Whisk |
  • 1 Tongs

Ingredients
  

  • 1 | lb | ground beef | 80/20 preferred
  • 4 | | burger buns |
  • 2 | large | onions | sliced
  • 4 | slices | American cheese |
  • 0.5 | cup | Hellmann’s mayonnaise | divided
  • 2 | tbsp | mustard |
  • 2 | tbsp | ketchup |
  • 1 | tbsp | Worcestershire sauce |
  • 1 | tsp | black pepper |
  • | | pickle slices | to taste
  • | | salt | to taste

Instructions
 

  • Slice the onions and cook them in a hot skillet with a squeeze of mayonnaise until soft and golden.
  • Add a splash of dark sauce to the onions and continue cooking until deeply caramelized and sticky.
  • In a bowl, mix mayonnaise, mustard, ketchup, pepper, and Worcestershire sauce until smooth.
  • Divide ground beef into 4 equal balls and keep cold.
  • Heat a griddle until very hot. Place a beef ball down, cover with parchment, and smash firmly with a spatula.
  • Season the smashed patties with salt and pepper. Cook until edges are crispy, then flip.
  • Top each patty with a slice of cheese and let it melt.
  • Toast the buns cut-side down on the griddle until golden.
  • Spread special sauce on the bottom buns, add pickles, cheesy patties, and caramelized onions. Top with the remaining buns and serve.

Notes

Store leftover sauce in the fridge up to 5 days.
Reheat patties briefly on a hot skillet to restore crispness.
Onions can be made a day ahead and reheated gently.
Use parchment paper when smashing to prevent sticking.