In N Out Fry Sauce Recipe: Secret Menu Copycat Blend

This copycat recipe brings the iconic West Coast flavor to your kitchen with a perfect balance of tangy and creamy. It’s the same sauce that makes In-N-Out’s fries unforgettable.

With just a handful of pantry staples, you can recreate this secret menu favorite in minutes. The result is a smooth, rich sauce that elevates fries, burgers, or even chicken tenders.

Ingredients for In N Out Fry Sauce

Nine pantry staples recreate that iconic West Coast magic in minutes.

The mayo is the base here. Hellmann’s or Best Foods for that classic American flavor—skip the light versions (they separate). Heinz ketchup is the standard, but any smooth tomato ketchup works. Sweet relish adds that signature tang—Vlasic is my go-to. Don’t skip the vinegar; it brightens everything up. Most grocery stores carry all of this in the condiment aisle.

No sweet relish? Diced pickles plus a pinch of sugar gets you close. Mustard can be swapped for Dijon for extra kick. Out of garlic powder? Fresh minced garlic at half the amount works, but the powder blends smoother. The paprika is more for color than heat—skip it if you’re out, but it does give that classic look.

This keeps in the fridge for 1-2 weeks in a sealed jar. The flavors meld after a few hours, so it tastes even better the next day. Stir before using—it’ll separate a bit. Perfect for fries, but try it on burgers too (worth it).

Step-by-Step Instructions for In N Out Fry Sauce

This copycat blend comes together in minutes with simple mixing and a quick rest.

Step 1: Combine the Base Ingredients

In a medium bowl, add the 0.5 cup Mayonnaise and 0.25 cup Ketchup. I like to start with these two because they form the creamy foundation of this sauce. Use a whisk or fork to blend them together until completely smooth and uniform in color.

This step ensures the mayonnaise and ketchup fully emulsify, preventing any separation later. The mixture should look like a pale pink-orange color with no streaks of either ingredient visible.

Step 2: Add the Tangy and Sweet Elements

Stir in the 2 tbsp Sweet Relish, 2 tsp Yellow Mustard, and 1 tbsp White Vinegar. The relish adds that signature sweetness and texture, while the mustard and vinegar bring the tangy kick that balances the richness.

Mix thoroughly for about 30 seconds until all ingredients are evenly distributed. You’ll notice the sauce starts to develop that familiar In-N-Out flavor profile—sweet, tangy, and slightly savory all at once.

Step 3: Incorporate the Spices

Sprinkle in the 0.5 tsp Garlic Powder, 0.5 tsp Onion Powder, 0.25 tsp Paprika, and 0.25 tsp Salt. These spices add depth and a subtle savory note that ties everything together.

Whisk again for another 30 seconds to ensure the spices are fully integrated. Taste and adjust the salt if needed, though the original recipe is perfectly balanced as is. The paprika adds a slight warmth and color, while the garlic and onion powders enhance the savory backdrop.

Step 4: Rest and Let the Flavors Meld

Cover the bowl with plastic wrap or transfer the sauce to an airtight container. Let it rest in the refrigerator for at least 1 hour before using. This resting time allows the flavors to meld together, creating that smooth, cohesive taste you expect from the original.

I’ve found that the sauce tastes even better after 24 hours, but if you’re in a hurry, 30 minutes will do in a pinch. Stir it once more before serving to redistribute any settled spices.

Perfect Pairings for This Dish

Classic Pairings

This sauce was designed for In-N-Out style fries—crispy on the outside, fluffy inside. I use russet potatoes cut into ¼-inch sticks and double-fried for that perfect texture. The sauce’s creaminess complements the hot, salty fries beautifully. 🔥

Burger Enhancements

Drizzle this on your next cheeseburger for an authentic West Coast experience. It pairs especially well with American cheese and a toasted brioche bun. I also love it on grilled chicken sandwiches for a tangy twist.

Unexpected Uses

Try this as a dip for chicken tenders or onion rings—it’s a game-changer. I’ve even used it as a spread for grilled cheese sandwiches instead of plain mayo. The sweet and tangy notes cut through rich, fried foods perfectly.

Veggie Delight

Don’t overlook vegetables! This sauce makes sweet potato fries or roasted Brussels sprouts irresistible. I toss 1 lb of sprouts with olive oil and roast at 400°F for 20 minutes, then drizzle with the sauce.

Breakfast Boost

Yes, even breakfast! A dollop on hash browns or mixed into scrambled eggs adds a fun, flavorful kick. I stir 1 tbsp into my eggs for a quick, tangy breakfast upgrade.

Frequently Asked Questions