Beef and Onion Smash Burgers

Thinly shaved onions cook into smashed beef on a very hot cast-iron surface, building a deep, lacy crust before the burgers are briefly steamed in soft buns.

35 min

4 burgers

A soft bun holds a thin beef patty edged with crisp browned onions, mustard, and dill pickle chips.

Ingredients

1 1/2 lb 80/20 ground beef

3 medium yellow onions (about 1 lb total), peeled

1 tsp kosher salt

1/2 tsp freshly ground black pepper

4 soft hamburger buns

2 tbsp yellow mustard

16 dill pickle chips

Equipment

Cast-iron griddle or large skillet · Thin, sturdy spatula · Instant-read thermometer · Lid or heatproof bowl · Sharp knife or guarded mandoline

Keep the crust intact

Once smashed, leave the patties alone until their browned edges loosen; pressing again squeezes out juices and hinders the crust.

Serve straight from the griddle

Assemble each burger as its batch finishes so the onion lace stays crisp beneath the soft bun.

Prepare and heat

01. Shave the yellow onions paper-thin and divide them into four generous piles.

02. Divide ground beef into four lightly formed balls; keep them loose for tender, thin patties.

03. Split buns and set out the mustard and pickle chips before cooking.

04. Heat cast iron on high for 6 to 7 minutes, until evenly hot with only a faint wisp of smoke.

Smash and brown

05. Cook two at a time: add beef balls, top with onion piles, smash firmly and thin, then season with salt and pepper.

06. Leave patties untouched for 2 to 3 minutes; turn only when edges are deeply brown and lacy and onions are softening.

Flip and check

07. Scrape fully beneath the crust and flip. Cook 1 to 2 minutes, checking sideways for 160 F; if needed, finish over medium-high in brief 20-second intervals.

Steam and serve

08. Set patties on lower buns, cap with top halves, and cover for 20 to 30 seconds to steam; repeat with the second batch.

09. Spread mustard on the bun tops, add four pickle chips per burger, close, and serve immediately.