While In-N-Out Burger is a widely known Cali staple and a reliable trump card in the East-versus-West debate, local L.A. burger aficionados know that there's something magical beneath the fast food joint's suspiciously stark menu. Enter the secret insider-only menu: specifically animal style, where gooey, cheesy, onion-y goodness takes center stage, and makes the already delish burger a true masterpiece. Every bite of this belly bomb is an otherworldly umami explosion. But now it looks like those of us who take pride in knowing this off-the-menu trick will have to share the wealth, as SeriousEats.com has broken down the recipe so that East Coasters in need of a fix can re-create this concoction at home. But burger snobs, take note: You won't find any truffle oil here. The In-N-Out burger is unrefined and uncomplicated, and we like it that way. So whip up some Thousand Island dressing, get those onions nice and goopy, and grill up those patties with a lot of love—and mustard. It's time to make this beast of a burger wherever you are, and keep it L.A. style!