In N Out Animal Fries

There is something about the smell of oil hitting 350 degrees that transports me straight to a cramped apartment kitchen in Portland, where my roommate Dave and I attempted to recreate In N Out Animal Style Fries at midnight after a concert. We had no business deep frying anything that late, but the craving was nonnegotiable. The oil splattered everywhere, the smoke alarm sang its opinions, and the fries were uneven and ugly. They were also the best thing either of us had ever eaten at that hour.

I have made these fries for Super Bowl parties, rainy Tuesday dinners, and one memorable camping trip where I smuggled a portable deep fryer into a state park. Every single time, someone grabs a fork, stares at the cheesy pile, and quietly says something inappropriate about how good it tastes. The caramelized onions are the real sleeper hit here. They take patience, but they transform from sharp and pungent into something sweet and savory that ties the whole dish together.

Ingredients

• Russet potatoes (900 g): Russets are the only potato worth using here because their high starch content is what gives fries that fluffy interior and crispy outside.
• Vegetable oil for frying: Use a neutral oil with a high smoke point like canola or peanut for the cleanest fry.
• Salt: Season immediately after the second fry while the potatoes are still glistening with oil so the salt sticks.
• Large onion, finely diced: One large onion might seem like a lot, but it cooks down significantly and you want enough to cover every single fry.
• Unsalted butter (2 tbsp): Butter gives the onions a richness that oil alone cannot replicate during the slow caramelization process.
• American cheese or cheddar slices (115 g): American cheese melts into that classic gooey blanket, but sharp cheddar works beautifully if you want more flavor punch.
• Mayonnaise (4 tbsp): This is the creamy base of the special sauce, so use a brand you genuinely enjoy eating on its own.
• Ketchup (2 tbsp): Adds sweetness and tomato tang that balances the richness of the mayo.
• Yellow mustard (1 tbsp): Just enough to give the sauce a subtle bite without making it taste like a mustard bomb.
• Sweet pickle relish (2 tsp): This is the ingredient that makes the sauce taste like the real deal, adding tiny pops of sweetness and texture.
• White vinegar (1 tsp): A splash of acidity that brightens the whole sauce and keeps it from tasting flat.
• Sugar (1/2 tsp): A tiny amount that rounds out the sharp edges of the vinegar and mustard.
• Paprika (pinch): More for color than flavor, but it adds a warm hint of smokiness.

Instructions

Heat the oil:

Pour vegetable oil into your deep fryer or a heavy pot to a depth of at least three inches and bring it to 180C (350F). Watch for tiny bubbles forming around a wooden spoon handle dipped in the oil, which tells you it is ready.

Prep and first fry:

Rinse the cut potatoes in a bowl of cold water to remove excess starch, then spread them on clean kitchen towels and pat completely dry. Fry them in small batches for 4 to 5 minutes until they are pale golden and tender inside but not yet crispy.

The second fry:

Crank the oil back up to temperature and return the parcooked fries for another 2 to 3 minutes until they turn deeply golden and the edges crackle when you lift them out. Hit them with salt the second they leave the oil.

Caramelize the onions:

Melt butter in a skillet over medium low heat, add the diced onions, and stir every minute or so for 12 to 15 minutes until they collapse into a dark, jammy, sweet mass. Do not rush this step by turning up the heat or you will get bitter char instead of caramelization.

Build the sauce:

Stir together the mayonnaise, ketchup, mustard, relish, vinegar, sugar, and paprika in a small bowl until evenly blended. Pop it in the fridge while you finish the fries so the flavors marry.

Melt the cheese:

Arrange your hot fries on a baking tray in a single layer, lay cheese slices over the top, and slide the tray under the broiler for 1 to 2 minutes. Watch it like a hawk because the line between beautifully melted and tragically burned is about 15 seconds.

Assemble and serve:

Scatter the caramelized onions generously over the cheese smothered fries, then drizzle the sauce in zigzag lines across the top. Serve immediately with extra sauce on the side because people will want more.

Save

One summer evening, I set a tray of these out on the patio table during a barbecue and watched three grown adults abandon their burgers midbite to hover over the fries. The conversation stopped entirely for about four minutes, broken only by the sound of forks scraping the tray clean. That tray never even made it to the actual dinner table. It was devoured standing up, paper tray and all, while the grill was still flaming.

Tools That Actually Help

A heavy bottomed pot or deep fryer is nonnegotiable because thin pots heat unevenly and your oil temperature will swing wildly between batches. A slotted spoon or spider strainer saves you from chasing floating fries around with tongs, which tends to splash hot oil. A rimmed baking tray for the broiling step keeps everything contained and makes for easy cleanup when the cheese inevitably bubbles over the edges.

Keeping Things Safe and Allergy Friendly

This recipe contains dairy from the butter and cheese, plus eggs from the mayonnaise, so it is not suitable for anyone with those allergies without substitutions. You can use a vegan mayo and plant based cheese slices to make it dairy free and egg free, though the melt will behave differently. Always double check labels on relish and mustard brands because some hidden allergens like gluten can lurk in unexpected places.

Getting Ahead and Making It Your Own

The special sauce improves dramatically after sitting in the fridge for a few hours, so mix it first and let it chill while you handle everything else. You can also caramelize the onions a day ahead and reheat them gently in the same skillet when you are ready to assemble. Frozen store bought fries work fine in a pinch and nobody at your party will complain once they are buried under cheese and sauce.

• Top with chopped dill pickles for a briny crunch that cuts through the richness.
• Add a few dashes of hot sauce over the finished tray if you want to wake the whole thing up.
• Remember that these fries wait for nobody, so have your guests seated and ready before you pull the tray from the broiler.

Save

Some recipes are about technique and others are about pure, unapologetic indulgence. These fries are firmly in the second camp, and they have never once disappointed anyone who has stood in my kitchen holding a fork.

Recipe FAQs

→ Can I use frozen fries instead of making them from scratch?

Yes, store-bought frozen fries work well as a time-saving shortcut. Bake or fry them according to the package directions until golden and crisp before adding your cheese, onions, and special sauce.

→ What type of cheese works best for these loaded fries?

American cheese slices melt the most smoothly and closely replicate the classic fast-food version. Cheddar cheese slices also work well if you prefer a sharper, more pronounced cheese flavor.

→ How do I get my fries extra crispy?

The double-frying method is key. The first fry cooks the potatoes through at a moderate temperature, while the second, shorter fry at the same heat creates a deeply golden, shatteringly crisp exterior. Always salt immediately after the second fry.

→ How far in advance can I make the special sauce?

The special sauce can be prepared up to 5 days in advance and stored in an airtight container in the refrigerator. Making it ahead actually improves the flavor as the ingredients have time to meld together.

→ What can I serve alongside these animal style fries?

These loaded fries pair perfectly with classic burgers, grilled hot dogs, or chicken sandwiches. They're also great alongside cold milkshakes or served as a shareable appetizer at gatherings and game-day parties.

→ How do I properly caramelize the onions?

Cook finely diced onions in butter over medium-low heat, stirring frequently. Patience is essential—true caramelization takes 12 to 15 minutes. The onions should turn a deep golden brown with a sweet, jammy consistency. Avoid turning up the heat to speed up the process, as this causes burning instead of caramelizing.