In-N-Out Smash Burger Tacos with Secret Animal Sauce Tips, FAQ & printable recipe

Tips for success

For the crispiest tortillas, make sure your griddle or skillet is thoroughly preheated before adding the beef-topped tortillas. You should see a slight wisp of smoke when you place them down.

Don't move them during the initial sear—let the beef develop a deep crust without interference. If you're making a large batch, keep the cooked tacos warm in a low oven (200°F) while you finish the rest.

When folding, use two spatulas for support if needed. Gently press the taco together to help it hold its shape, but don't squeeze too hard or the filling will spill out.

Serve the tacos immediately with extra sauce on the side for dipping. If you like a little heat, serve with sliced jalapeños or a drizzle of hot sauce. These tacos are best enjoyed fresh, but you can also cut them in half for easier eating.

Variations

• Spicy Smash Burger Tacos: Add a sliced jalapeño or a drizzle of your favorite hot sauce to each taco before folding. You can also mix a pinch of cayenne into the secret sauce for an extra kick.
• Bacon Smash Burger Tacos: Cook a few slices of bacon until crispy, crumble, and sprinkle over the melted cheese before adding the lettuce and sauce. The smoky flavor pairs perfectly with the beef.
• Avocado Smash Burger Tacos: Add sliced or mashed avocado to each taco along with the lettuce and onions. The creamy avocado complements the tangy sauce and adds a fresh, buttery texture.
• BBQ Smash Burger Tacos: Swap the secret sauce for your favorite barbecue sauce, or mix a tablespoon of BBQ sauce into the animal sauce for a smoky twist. Top with crispy fried onions for extra crunch.

Storage and make-ahead

Fridge

Store leftover tacos in an airtight container in the refrigerator for up to 2 days. Keep sauce separate to prevent sogginess.

Freezer

Freeze cooked tacos for up to 1 month. Reheat in a toaster oven or air fryer to restore crispiness.

Reheat

Reheat in a toaster oven at 350°F for 5-7 minutes, or in an air fryer at 375°F for 3-4 minutes, until hot and crispy.

Store leftover tacos in an airtight container in the refrigerator for up to 2 days. To keep them from becoming soggy, store the sauce separately and add it fresh when reheating. The tortillas may soften, but they will still taste good.

The secret sauce can be made up to 5 days in advance and kept refrigerated. The caramelized onions can also be prepared ahead and stored in the fridge for up to a week. You can press the beef onto the tortillas a few hours before cooking, but keep them refrigerated until ready to sear.

Serving ideas

Serve these smash burger tacos hot off the griddle, with extra secret sauce on the side for dipping. They pair beautifully with a cold, crisp salad or a simple slaw.

For a fun presentation, arrange them on a platter with lime wedges and pickled jalapeños. These tacos are also great for parties—just set up a taco bar with extra toppings like diced tomatoes, sliced avocado, or hot sauce.

For a complete meal, serve with a side of crispy fries or a light cucumber salad. The creamy, tangy sauce also works well as a dip for fries or vegetables.

If you're serving a crowd, you can double the recipe and cook in batches, keeping the finished tacos warm in a low oven. These tacos are best enjoyed immediately, so plan to serve them as soon as they're done.

Frequently asked questions

Recipe card

In-N-Out Smash Burger Tacos with Secret Animal Sauce

Prep 15 minCook 20 minTotal 35 minServes 4

Ingredients

• 1 cup mayonnaise
• 4 tbsp ketchup
• 1 tbsp Dijon mustard
• 1 tsp Worcestershire sauce
• 1 tsp white vinegar
• 2 tbsp sweet pickle relish
• 1/4 cup caramelized onions
• 1/2 tsp garlic powder
• 1/4 tsp black pepper
• 1 lb 80/20 ground beef
• 8 mini flour tortillas
• Salt to taste
• 8 slices American cheddar cheese
• 2 cups shredded iceberg lettuce
• 1/2 cup caramelized onions

Instructions

1. In a medium bowl, combine the mayonnaise, ketchup, Dijon mustard, Worcestershire sauce, white vinegar, sweet pickle relish, 1/4 cup caramelized onions, garlic powder, and black pepper. Whisk until smooth and pink. Set aside.
2. Divide the ground beef into 8 equal portions, about 2 tablespoons each. Place a portion onto a mini tortilla and press it firmly into an even layer that covers the surface, leaving a small border. Season lightly with salt.
3. Heat a griddle or large cast-iron skillet over high heat until smoking. Place the tortillas beef-side down on the hot surface. Cook for 4 minutes without moving, until the beef is deeply browned and crispy.
4. Flip each tortilla so the beef side is up. Immediately place a slice of American cheddar on the hot beef. Cook for 1-2 minutes, until the cheese melts and becomes bubbly.
5. Pile a generous handful of shredded iceberg lettuce over the melted cheese, followed by a spoonful of the remaining caramelized onions.
6. Drizzle the secret animal sauce generously over the lettuce and onions, letting it cascade down the sides.
7. Carefully fold each taco in half, pressing gently to keep the filling inside. Serve immediately while hot and crispy.

Contains: gluten, eggs, milk, fish, mustard

Estimated nutrition per serving

Calories

580

Protein

28 g

Carbohydrates

30 g

Fat

38 g

Automatic estimate from the ingredient list, not laboratory-verified.