Copycat In-N-Out Animal Style Burger

• 1 lb ground chuck (80/20 fat ratio)
• 4 soft hamburger buns
• 8 slices real American cheese
• 2 large yellow onions, finely diced
• 2 tbsp butter (for caramelizing onions)
• 2 tbsp yellow mustard (for searing patties)
• 12 slices dill pickle chips
• 4 leaves crisp iceberg lettuce
• 4 slices ripe tomato
• Spread recipe 1/2 cup mayo + 3 tbsp ketchup + 2 tbsp sweet relish + 1 tsp vinegar

Instructions

1. 1

   Melt butter in a skillet over medium-low heat. Add diced onions with a pinch of salt and cook slowly for 20-25 minutes, stirring often, until deep golden-brown and caramelized. Set aside.

2. 2

   Whisk together mayonnaise, ketchup, sweet pickle relish, and white vinegar in a bowl to make In-N-Out Spread.

3. 3

   Divide beef into 8 equal small balls (2 oz each). Heat a heavy cast iron griddle or skillet over high heat.

4. 4

   Place beef balls on hot griddle and smash down paper-thin with a firm spatula. Season generously with salt and pepper. Spread 1 tsp yellow mustard on the raw top of each patty.

5. 5

   Sear for 2 minutes until edges are deeply caramelized and crispy. Flip so mustard side sears on the griddle. Immediately top each patty with a slice of American cheese and 1 tbsp grilled onions.

6. 6

   Stack two patties together. Toast buns on the griddle. Spread sauce on bottom bun, add pickles, tomato, and lettuce, then stack the cheesy double patties and cap with top bun.