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Croissant Smash Burgers

Croissant smash burgers with deeply seared thin patties and melty American cheese, served on toasted, golden croissant halves. This method uses caramelized onions plus a tangy mayo-ketchup-pickle sauce for a crisp, juicy, burger-night twist.
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Prep Time 30 minutes
Cook Time 25 minutes
chill 10 minutes
Total Time 1 hour 5 minutes
Servings: 4 servings
Course: Dinner
Cuisine: American
Calories: 830
Ingredients Equipment Method Notes

Ingredients
  

Beef patties and croissant buns
  • 1.5 lb ground beef (80/20) 80/20 for better browning and juiciness.
  • 4 croissants, halved Use store-bought croissants for quickest results.
  • 4 slices American cheese or sharp cheddar Cheese goes on during the last minute to melt over the patties.
  • 4 iceberg lettuce, sliced tomatoes Plan for both lettuce and tomato in the assembly.
  • 1 salt and pepper, to taste Season patties and croissant toast as needed.
For the caramelized onions
  • 2 large white onions, diced Dice evenly so they caramelize uniformly.
  • 1 tbsp olive oil Helps onions cook gently while browning.
  • 2 tbsp butter Adds richness and golden color.
  • 1 tsp granulated sugar Aids caramelization.
  • 0.5 tsp salt Balances sweetness as onions soften.
For the sauce
  • 1 cup mayonnaise Creamy base for the tangy sauce.
  • 0.25 cup ketchup Adds sweetness and acidity.
  • 0.25 cup caramelized onions Use the cooled onions from the caramelizing step.
  • 0.25 cup finely chopped pickles Brings crunch and tang.
  • 1 tbsp yellow mustard Rounds out the flavor.
  • 1 tsp vinegar Brightens the sauce.
  • 1 tsp sugar Optional sweetness to balance vinegar.

Equipment

  • 1 cast iron skillet
  • 1 sheet pan

Method
 

Make the sauce
  1. Whisk together mayonnaise, ketchup, yellow mustard, chopped pickles, vinegar, sugar, salt, and pepper for the sauce until smooth, then refrigerate for 10 minutes.
  2. While the sauce chills, finish prepping the caramelized onions so the sauce can be combined with them at serving time.
Caramelize the onions
  1. Heat olive oil and butter in a pan over low heat, then add diced onions and granulated sugar.
  2. Cook the onions slowly for 15 to 20 minutes, stirring occasionally, until soft and golden, then set aside to cool.
Form and season the smash patties
  1. Divide the ground beef into 4 portions, roll into balls, and flatten into thin patties.
  2. Season one side of each patty with salt and pepper so the sear side browns evenly.
Toast croissants
  1. Toast croissant halves, cut-side down, in a dry skillet over medium heat until golden and crisp.
  2. Transfer the toasted croissants to a warm surface so they stay crisp while you cook the patties.
Smash, sear, and melt cheese
  1. Cook patties in a hot skillet for 2 minutes per side, pressing lightly only as needed to keep them thin.
  2. During the last minute of cooking, top each patty with American cheese or sharp cheddar and continue until melted.
Assemble the burgers
  1. Spread sauce on the toasted croissant halves, then layer on lettuce and tomato.
  2. Top with caramelized onions and the cheese-melted patties, and close the croissant smash burgers to serve immediately.

Notes

For the best texture, keep patties thin and don’t overcook—remove them when cheese is melted and edges are deeply browned. Refrigerate leftover sauce up to 4 days; store assembled burgers only for a few hours for maximum crunch, and freeze patties (cooked or uncooked) for up to 2 months. For a lighter option, swap to reduced-fat cheese and use leaner ground beef, noting the browning may be slightly less rich.