In-N-Out Sauce (Copycat Burger Sauce Recipe)

If you have ever taken one bite of an In-N-Out burger and thought, “What is on this thing?” — that creamy, tangy, slightly sweet spread is exactly what this recipe is about.

This copycat In-N-Out sauce recipe nails that iconic flavor using seven pantry ingredients you already have sitting in your kitchen right now. No drive-thru. No road trip to California. No mystery.

I have made this In-N-Out burger sauce copycat recipe more times than I can count — tweaking the mayo ratio, testing sweet relish against dill, chilling it for different lengths of time — until it hits that exact balance the restaurant gets right every single time. The result is a burger sauce so close to the original spread that the only real difference is that you made it yourself.

Spread it. Dip it. Drizzle it. This is the last burger sauce recipe you will ever need.

Most people assume the secret is some exotic ingredient nobody has heard of. It is not. The secret is the ratio.

Every element in this In-N-Out Burger sauce copycat has a job. The mayonnaise creates the creamy base that makes the sauce cling to the bun instead of sliding off. The ketchup brings tomato sweetness and that faint red color that tells you instantly what you are dealing with. The yellow mustard cuts through the richness with just enough sharpness — not enough to taste like mustard, but enough to stop the sauce from being flat. The white vinegar is the one ingredient most home cooks skip, and it is the one ingredient that makes this taste like the real thing. It lifts everything, adds the tang that lingers after every bite, and keeps the sauce from tasting heavy. The sweet pickle relish ties it all together — tiny bursts of sweet, briny flavor that mimic exactly what you taste when you bite into an In-N-Out burger with Spread on it.

Get the ratio right, and you get the sauce right. That is the whole story.

This is also why the In-N-Out sauce recipe copycat recipes you find on Reddit get mixed results. Some people go heavy on the ketchup and end up with something closer to fancy ketchup than burger sauce. Some skip the vinegar entirely and wonder why it tastes flat. The recipe below has been tested and balanced, so you do not have to guess.

In-N-Out calls it “Spread.” It sits on their not-so-secret menu right alongside Animal Style and Protein Style. Every single burger that leaves that kitchen has this sauce on it — whether you ask for it or not.

It is a mayo-based burger sauce that pulls from the same flavor family as Thousand Island dressing, but it is not Thousand Island dressing. Thousand Island is thicker, heavier, and loaded with more ingredients. The In-N-Out spread is cleaner, tangier, and slightly lighter — which is exactly why it works so well on a smashed beef patty without overwhelming every other topping on the burger.

When you order Animal Style, the kitchen doubles the Spread on your burger, adds mustard-seared patties and caramelized onions, and hits it with extra pickles. The sauce is the same. They just use more of it. Which means this In-N-Out Burger sauce copycat recipe gives you the full Animal Style experience at home — you just control how much you pile on.

The Only Smash Burger Sauce Recipe You’ll Ever Need

Seven ingredients. All of them are sitting in your kitchen right now.

½ cup mayonnaise — Use real, full-fat mayo. Hellmann’s or Best Foods work best. Miracle Whip is not mayo and will ruin the flavor profile entirely. The creaminess of real mayo is the foundation on which this sauce is built.

3 tablespoons ketchup — Standard ketchup. Heinz is reliable. The ketchup brings sweetness, color, and a faint tomato depth that balances the tang from the vinegar.

1 teaspoon yellow mustard — Classic American yellow mustard. Not Dijon. Not whole grain. Yellow mustard has the right sharpness-to-smoothness ratio for this sauce.

1 teaspoon white vinegar — This is the ingredient that separates a great copycat from a mediocre one. White vinegar adds the tangy lift that makes the sauce taste bright instead of heavy. Do not skip it.

2½ tablespoons sweet pickle relish — Sweet, not dill. The sweetness from the relish plays against the vinegar to create that signature back-and-forth flavor that makes this sauce addictive. Dill relish pushes the sauce into a different territory entirely.

Pinch of salt — Just enough to sharpen the flavors without making the sauce taste salty.

Pinch of black pepper — A subtle background note that adds depth without announcing itself.

Step 1 — Combine Everything in One Bowl

Add the mayonnaise, ketchup, yellow mustard, white vinegar, sweet pickle relish, salt, and black pepper to a medium mixing bowl. There is no specific order that matters here — everything goes in together.

Step 2 — Whisk Until Completely Smooth

Use a small whisk or fork and mix until the sauce is fully combined and creamy. You will still see small pieces of relish — that is normal and exactly how it should look. What you want to eliminate is any visible streaks of ketchup or mustard sitting unmixed in the mayo.

Step 3 — Chill Before Serving

Cover the bowl with plastic wrap or transfer the sauce to a jar with a lid. Refrigerate for at least 30 minutes before serving. One hour is better. Overnight is best.

This step matters more than most people realize. Right out of the bowl, the sauce tastes sharp and slightly disjointed — you can pick out each ingredient. After 30 minutes in the fridge, the vinegar softens into the mayo, the relish infuses its sweetness throughout, and the mustard settles into the background. The sauce becomes one unified flavor instead of seven separate ones. That is when it tastes like the real In-N-Out Spread.

Step 4 — Serve

Spread it generously on your burger bun. Spoon it over fries. Use it as a dip. Double it up Animal Style. However you use it — use more than you think you need. This sauce rewards generosity.

Every competitor recipe tells you to chill the sauce. Almost none of them explain why it actually works — and why skipping it is the single biggest mistake home cooks make with this recipe.

When you first mix mayo, vinegar, and relish together, the ingredients are chemically separate. The vinegar sits on top of the fat in the mayo instead of binding to it. The relish brine has not had time to bleed into the surrounding sauce. The mustard is sharp and forward.

Thirty minutes of refrigeration changes all of that. The cold temperature slows the molecules down and forces the ingredients to bind together properly. The emulsification — the creamy, uniform texture that makes this sauce feel like one thing instead of many things — happens in the fridge, not in the bowl.

Make this sauce the night before burger night. By the time you are ready to eat, it will taste closer to the real In-N-Out Spread than anything you have ever made at home.

Sweet relish — not dill. This is the most common mistake in every In-N-Out Burger sauce recipe Reddit thread. Dill relish makes the sauce taste like a pickle jar. Sweet relish creates the balanced tang-sweetness that defines the original. If you only have dill, add ½ teaspoon of sugar to compensate.

Real mayo only. Reduced-fat mayo works in a pinch. Whipped dressings like Miracle Whip do not. The texture and flavor of Miracle Whip are so different from real mayo that the sauce will not come together correctly.

Vinegar is not optional. If you have ever made this sauce and thought it tasted flat, you either skipped the vinegar or did not use enough. That single teaspoon is what makes this taste like the restaurant version and not just mayo mixed with ketchup.

Too thick? Too thin? If the sauce is thicker than you want, whisk in ¼ teaspoon of white vinegar at a time until it reaches your preferred consistency. If it is too thin — which is rare — whisk in a small additional spoonful of mayo.

Make a double batch. This sauce keeps in the refrigerator for up to five days in an airtight container. It also gets better on days two and three. Make more than you think you need and thank yourself later.

The obvious answer is burgers. But this sauce works on almost everything you put it near.

On smash burgers — Spread it on both the top and bottom bun before you stack the patties. If you want the full Animal Style experience, double the sauce, add caramelized onions, and pile on extra pickles.

On fries — Animal Style fries from In-N-Out come loaded with this sauce, caramelized onions, and melted cheese. Replicate that at home with a pile of crispy fries, a generous spoon of this copycat sauce, and however much cheese you can justify.

As a dipping sauce — Chicken tenders, onion rings, mozzarella sticks, roasted potatoes — this sauce works as a dip for anything you would normally reach for ranch or ketchup with.

On sandwiches and wraps — Swap out plain mayo on any sandwich and use this instead. It adds enough flavor to make a simple turkey and cheese sandwich feel like something worth looking forward to.

On grain bowls — Drizzle it over a rice bowl with grilled chicken or beef, shredded lettuce, tomato, and pickles. It turns a plain bowl into something that tastes assembled with intention.

Transfer the sauce to an airtight container or a glass jar with a tight lid. Store it in the refrigerator for up to five days.

Do not freeze it. Mayo-based sauces break down when frozen — the emulsion separates, and the texture becomes grainy and watery when thawed. There is no recovering it after that. Since this recipe takes five minutes to make, there is no reason to freeze it anyway.

If the sauce separates slightly in the fridge after a few days, give it a quick whisk or stir before using. It will come back together immediately.