🍔 In-N-Out-Inspired Burger
The move worth learning here is the mustard griddle. You paint a thin layer of yellow mustard onto the raw top of the patty a moment before you flip it, and it caramelizes into the crust instead of sitting on the burger as a condiment — tangy, faintly scorched, and nothing like mustard squeezed on afterwards. Add sweet griddled onions and a pink, pickle-flecked spread and you have the off-menu "animal style" build that the California chain is known for. Ours is an independent recreation; the chain keeps its own recipe proprietary.
What the original is known for
In-N-Out is known for fresh, thin griddled patties, American cheese, a tangy pink spread, and the cult "Animal Style" option with mustard-griddled patties and caramelized grilled onions. Simplicity and freshness define the flavor.
🧾 In-N-Out-Inspired Burger — Recipe Card
From I Love Hamburger — ilovehamburger.com · Inspired-by recipe, not affiliated with In-N-Out.
Ingredients
- 1 lb (450g) ground beef, 80/20 chuck
- 4 soft hamburger buns
- 4 slices American cheese
- 4 tomato slices
- 4 leaves iceberg lettuce
- 1 large white onion, half thinly sliced (for grilling), half in rings (raw)
- Yellow mustard, for the "animal-style" griddled patties (optional)
- For the spread: 1/3 cup (75g) mayonnaise, 2 tbsp (30g) ketchup, 1 tbsp (15g) sweet pickle relish, 1 tsp white vinegar, pinch of sugar
- Kosher salt and black pepper
Instructions
- Make the spread by stirring together the mayo, ketchup, relish, vinegar and sugar; chill. (Or use our dedicated spread recipe — see the sauce note.)
- For grilled onions: cook the thinly sliced onion on a griddle over medium heat with a pinch of salt, stirring, until soft, sweet and golden, 8–10 minutes. (These are quick griddled onions, not the fully caramelized 25–30 minute kind.) Set aside.
- Roll the beef into 4 loose balls (or 8 for doubles). Keep them loose and leave them unseasoned for now — salting raw beef draws moisture to the surface and costs you crust.
- On a screaming-hot griddle, lay a piece of parchment over each ball and smash hard and flat for about 10 seconds, until the patty is thin and slightly wider than the bun. Peel the parchment away and season the smashed top with salt and pepper.
- Cook undisturbed about 2 minutes, until the edges are deep brown and lacy. For "animal-style," smear the seasoned top with a thin layer of yellow mustard just before flipping so it griddles into the crust.
- Scrape under the patty with a stiff, thin spatula, flip, add American cheese, and cook to 160°F (71°C) internal. Toast the buns.
- Spread sauce on both buns and build (see assembly). Serve hot.
🍖 The patty
Thin, fresh, griddle-seared patties — single or double. Smash loose balls straight onto the hot griddle and season after the smash, never before. For "animal style," paint the top of the patty with yellow mustard right before flipping so it griddles into a tangy, caramelized crust.
🥫 The sauce
The tangy pink spread is essential. Use our dedicated In-N-Out-Inspired Spread recipe, or the quick version in the ingredient list above.
🍔 How to assemble
- Bottom bun → spread → tomato → lettuce → cheese-topped patty (add grilled onions here for animal-style).
- For a double, stack a second cheese-topped patty.
- Spread the top bun, crown the burger, and serve immediately.
🔁 Substitutions & variations
- Make it a "Double-Double" style with two thin patties and two slices of cheese.
- Skip the mustard-griddle step for the standard (non-animal) version.
- Use raw onion rings instead of grilled onions for a sharper, fresher bite.
- For gluten-free, use a GF bun and confirm your relish is GF.
Burger HQ Picks Recommended Tools for This Recipe
Heavy-Duty Stainless Smash Burger Press
A flat, weighty press is the difference between a real lacy-edged smash burger and a sad steamed puck. Round, broad face for full patty contact.
Check price →Outdoor Gas Flat-Top Griddle
A big flat top cooks a dozen smash burgers at once with room for onions and buns. The backbone of burger night for a crowd.
Check price →Thin Flexible Stainless Turner (Smash Spatula)
A stiff, thin, bevelled edge slides under the crust and scrapes up every bit of the browned fond instead of tearing the patty.
Check price →Infrared Surface Thermometer
Reads the griddle surface itself, not the air — the only way to know you are actually at the 425–475°F a smash burger needs before the beef goes down.
Check price →As an affiliate site, I Love Hamburger may earn a commission from qualifying purchases. This does not affect our recommendations.
Frequently asked questions
Is this how In-N-Out actually makes their burgers?
Nobody outside the company can say — the recipe is proprietary. This page is our own reverse-engineering of the flavors, written with no affiliation with, endorsement from, or permission of In-N-Out. It gets you thin griddled patties, melty American cheese, a tangy spread, and the mustard-griddled animal-style option.
What is "animal style"?
It's a fan term for a mustard-griddled patty topped with extra spread, pickles and caramelized grilled onions. Our recipe shows the mustard-griddle and grilled-onion steps so you can build it that way.
How do I get the spread right?
Balance mayo and ketchup with a little relish, vinegar and sugar. Our In-N-Out-Inspired Spread has the tuned ratios.