In-N-Out Animal Style Fries (Copycat Recipe)

If I’m at In-N-Out, I’m getting In-N-Out animal style fries. They’re crispy, cheesy, and covered in grilled onions and that tangy secret sauce.

Since I live on the East Coast and there’s no In-N-Out anywhere near me, I had to figure out how to make them at home. Turns out, it’s pretty easy, and they taste sooo good!

overhead view of In-N-Out Animal Style Fries (Copycat Recipe) on a sheet pan

Why You’ll Love This Recipe

Crispy fries, melty cheese, and the best toppings – Just like the real thing.
No drive-thru needed – Make them whenever the craving hits.
Great for sharing – Perfect as a side or a snack.

Equipment List

✔ Cutting board & sharp knife – For cutting the potatoes and dicing onions.
✔ Large bowl – For soaking the fries in ice water.
✔ Wire rack – To drain and cool the fries between steps.
✔ Large pot – For boiling the fries.
✔ Slotted spoon or tongs – For removing fries from the boiling water and fryer.
✔ Heavy-bottomed pot or deep fryer – For frying the fries.
✔ Cooking thermometer – To keep the oil at the right temperature.
✔ Mixing bowl – For making the secret sauce.
✔ Small skillet – For caramelizing the onions.
✔ Spatula or wooden spoon – For stirring the onions as they cook.
✔ Paper towels – For draining any excess oil after frying.
✔ Baking sheet – If using the oven to help melt the cheese.

Ingredients

Animal style fries are all about the toppings. You’ll need fries (frozen or fresh-cut), American cheese for that classic melt, grilled onions, and the signature sauce. The sauce is a mix of mayo, ketchup, mustard, relish, vinegar, and a little sugar—super easy to throw together.

What You’ll Need

For the Fries:

Russet potatoes – The best for crispy fries. Yukon Golds work too, but won’t be as light.
Cold water + ice – Helps remove starch and keeps them firm.
Salt + vinegar – Helps soften the inside without breaking them down.
Avocado oil – For frying. It has a high smoke point, so it works great for crispy fries.

For the Caramelized Onions:

Yellow onions – Sweet and perfect for caramelizing. White onions work too, but they’re a little sharper.
Butter + avocado oil – A mix gives them a rich flavor. All butter works, but they might brown faster.
Salt + a splash of water – Helps soften and caramelize.

For the Secret Sauce:

Mayonnaise – The base of the sauce. Light mayo works too.
Ketchup – Adds sweetness and color.
Sweet pickle relish – The key ingredient! Dill relish gives a sharper taste.
Distilled white vinegar – Adds the right tang. Apple cider vinegar works in a pinch.

For Topping:

American cheese slices – Melts perfectly over hot fries. Cheddar works but won’t be as smooth.

How to Make Animal Style Fries

Step 1: Cut the Potatoes

I wash and peel the potatoes (peeling is optional). Then, I cut them into ¼-inch thick strips, just like In-N-Out.

Step 2: Rinse and Soak

I rinse the fries in cold water a few times to remove extra starch. Then, I soak them in ice water for 15–30 minutes—this keeps them firm and helps them fry evenly.

Step 3: Boil the Fries

I bring a pot of salted water with a splash of vinegar to a boil, then add the fries. They only need 3 minutes—just enough to slightly soften the inside.

Step 4: Let Them Dry

I carefully remove the fries and place them on a wire rack. They need to dry completely before frying, so I let them sit while I make the onions and sauce.

Top Tip: The Secret to Perfect Caramelized Onions

Cooking onions low and slow brings out their natural sweetness. I let them cook for at least 15 minutes, stirring occasionally. If they start sticking, I add a splash of water to keep them soft and jammy.

Step 5: Make the Caramelized Onions

While the fries dry, I heat butter and a little avocado oil in a pan over medium-low heat. I add chopped onions and a pinch of salt and cook them slowly for 15-20 minutes, stirring occasionally, until they’re golden and soft.

Step 6: Make the Secret Sauce

In a small bowl, I mix together:

Mayonnaise
Ketchup
Sweet pickle relish
Distilled white vinegar

I stir it up until it’s smooth and creamy, then set it aside.

Step 7: First Fry

I heat avocado oil to 330°F and fry the fries in small batches for 4-5 minutes, just until they’re lightly golden. I place them back on the wire rack to drain.

Step 8: Chill the Fries

Now for the key step—I put the fries in the freezer for 15 minutes. This helps them stay crispy after the second fry.

Step 9: Second Fry

I heat the avocado oil to 375°F and fry the fries again for 3-4 minutes, until they’re deep golden brown and crispy. Then I drain them on the rack and sprinkle with salt.

Shortcut Tip: Use Frozen Fries

Don’t feel like making fries from scratch? Grab a bag of frozen fries. Thick-cut or crinkle fries work best since they hold up under all the toppings. Bake or air-fry them according to the package, then add the cheese, onions, and sauce. Done!

Step 10: Assemble the Animal Style Fries

I place the hot fries on a serving plate.
I layer on American cheese slices so they start melting.
I spoon the caramelized onions evenly over the cheese.
I drizzle the secret sauce all over the top.

If you’re feeling like baked fries, try this baked version – Loaded Fries with Bacon Cheddar and Ranch.

Top Tip: Want Extra Melty Cheese?

If the cheese isn’t melting fast enough, I pop the fries in a warm oven for 1-2 minutes before adding the sauce. This makes them extra gooey!

How To Serve It

These fries are best eaten right away while the cheese is melty. If you want the full In-N-Out experience, serve them with a burger and a milkshake.

Have you made animal style fries at home? What’s your favorite way to serve them? Let me know in the comments!