The 3×3 is three beef patties, three slices of American cheese, caramelized onions, crisp iceberg, ripe tomato, and a tangy mayo-ketchup spread — all stacked on a toasted sesame bun. In-N-Out only officially sells up to the Double-Double, so if you want a 3×3, you either live near one and know to ask, or you make it yourself. This recipe gives you the full build at home, with real control over the beef and the cook.
What makes this version work
Two things matter most here. First, the fat content: 80/20 ground beef keeps each patty juicy through a hot, fast sear. Leaner beef dries out fast, especially when you’re cooking three patties back to back on a screaming-hot cast iron or griddle. Second, patty thickness. Keep each one around 4 ounces and press it fairly thin before it hits the pan — you want maximum contact with the surface so you get a proper browned crust, not a steamed puck. That crust is where the flavor lives, and it’s what holds the whole stack together without turning into a dense brick. Get those two things right and the rest of the build falls into place.
Smart swaps
- American cheese: Deli-sliced American melts far better than the individually wrapped singles — worth the small upgrade. If you can’t find it, a mild white cheddar will work but won’t melt as smoothly.
- Sweet pickle relish in the spread: Finely chopped bread-and-butter pickles are a solid substitute if relish isn’t in the pantry.
- Yellow onions for caramelizing: White onions work fine. Sweet (Vidalia) onions cook down faster and go jammier — good swap if you’re short on time.
- Sesame seed bun: Any soft, medium-weight bun holds up here. Avoid anything too thick or crusty — it throws off the meat-to-bun ratio and makes the whole thing hard to eat.
Make-ahead notes
The spread keeps in the fridge for up to five days in a sealed container — make a double batch and use it all week. Caramelized onions refrigerate well for three to four days; reheat them in a small pan over low heat with a splash of water to loosen them up. Raw patties can be shaped, separated with parchment, and refrigerated up to 24 hours ahead, or frozen for up to two months — thaw overnight in the fridge before cooking. Don’t season the patties until right before they go in the pan; salting too early draws out moisture and works against that crust you’re after.
If something goes sideways
- Patties are shrinking into thick pucks: The beef was probably packed too tightly or not pressed thin enough before cooking. Shape them loosely and smash them down firmly in the pan during the first 30 seconds — before the crust sets.
- Cheese isn’t melting: Add a few drops of water to the pan right after you lay the cheese on, then cover with a lid or a metal bowl for 30 to 45 seconds. The steam does the job fast.
- Burger is falling apart when you pick it up: The stack needs a few minutes to settle after assembly — don’t cut or lift it immediately. A gentle press with your palm and a 60-second rest lets everything compress slightly and hold.
- Spread tastes flat: It needs acid. Add a small splash more of vinegar, taste again, and adjust. The spread should have a noticeable tang — if it just tastes like pink mayo, it’s underseasoned.
- Bun is soggy before you finish building: Toast the bun cut-side down in butter until it’s genuinely golden, not just warm. A properly toasted bun resists the spread and tomato juice long enough to eat the whole thing without it collapsing.
In-N-Out Style 3x3 Burger
Ingredients
For the Beef Patties & Cheese:
- 12 oz ground beef (80/20) formed into three 4 oz patties
- 3 slices American cheese preferably deli-style for optimal melt
For the Burger Components:
- 1 piece sesame seed hamburger bun soft and slightly sweet preferred
- 1 tbsp unsalted butter for toasting the bun
- 1 medium tomato sliced; choose vine-ripened and juicy
- 1 leaf iceberg lettuce washed and crisped
- ¼ medium yellow onion sliced and caramelized
For the In-N-Out Style Spread:
- 2 tbsp mayonnaise
- 1 tbsp ketchup
- 1 tsp sweet pickle relish
- ½ tsp white vinegar
- 1 pinch paprika
Instructions
- Prepare the Spread: In a small bowl, combine mayonnaise, ketchup, sweet pickle relish, white vinegar, and paprika. Mix until smooth. Chill until ready to use.
- Caramelize the Onions: In a skillet over medium heat (330°F / 165°C), add a splash of oil and sauté sliced onions. Stir occasionally for 10–12 minutes until golden and jammy. Set aside.
- Toast the Bun: Heat 1 tbsp of butter in a skillet on medium heat. Place bun halves cut-side down and toast until golden brown, about 2–3 minutes. Remove and set aside.
- Cook the Patties: Heat a cast iron skillet or griddle over high heat (400°F / 200°C). Generously season each patty with salt and pepper. Sear each patty for 2–3 minutes per side. Add a slice of American cheese atop each patty after the flip, allowing to melt as it finishes.
- Assemble the Burger: Spread a generous layer of the secret spread on the bottom bun. Layer on the tomato slice, crisp lettuce, first cheesy patty, spoonful of grilled onions, second cheesy patty, more onions, final cheesy patty, and top bun. Press gently to hold together.
Notes
- Use freshly ground beef for the juiciest patties.
- Place each patty on a square of parchment for easy transferring and smoothing edges into a round.
- For a spicier twist, add 2–3 slices of pickled jalapeños between layers.
- Brioche buns may be used for a gourmet variation.
Nutrition
Common questions
What internal temperature should the beef patties reach?
Cook ground beef patties to 160°F (71°C) internal temperature. Unlike a whole-muscle steak, ground beef can carry bacteria throughout the meat, so it needs to be fully cooked — use an instant-read thermometer if you’re unsure.
Can I use a regular skillet instead of cast iron?
Yes, a heavy stainless steel pan works. The key is getting it genuinely hot before the patties go in — cast iron just holds heat more evenly, which is why it’s recommended.
How do I stop the stack from being impossible to eat?
Press the assembled burger down firmly but steadily with your palm right after you build it, then let it sit for about a minute before picking it up. Skewering it through the center with a long toothpick or skewer also helps keep the layers aligned.
Can I make the caramelized onions faster?
You can speed them up slightly by adding a pinch of baking soda to the pan, which accelerates browning. Be careful — it also makes them softer faster, so watch them closely and pull them off heat as soon as they’re golden and jammy.
Is there a way to keep the cooked patties warm while I finish cooking all three?
Rest finished patties on a wire rack set over a baking sheet in a 200°F (93°C) oven. Skip the plate — stacking them traps steam and softens the crust you just worked to build.
What’s the best way to get the spread ratio right?
Taste it before it goes on the bun — it should be creamy, tangy, and slightly sweet in roughly that order. If the sweetness from the relish is dominating, add a little more vinegar and a small pinch of salt to bring it back into balance.
If you liked this one
- Perfect In-N-Out 2×2 Copycat
- Animal Style Burger Recipe
- Animal Style Cheeseburger Recipe
- Triple Cheeseburger Copycat Recipe