This Classic In-N-Out Treat Wasn't On The Original Menu
In-N-Out is to Californians as Whataburger is to Texans and Dunkin' Donuts is to New Englanders. The legendary fast food chain with its famed crossed palm trees has become rooted in California history and tourism since 1948, when it became the first drive-thru hamburger joint in the whole state (via In-N-Out). Within the same year of the store's grand opening, founder Harry Snyder invented the "two-way speaker box," which allowed paying customers to place their food orders via the comfort of their own car. They never had to step foot outside of the vehicle and In-N-Out employees weren't having to rush in and out of the kitchen to fulfill orders. It was the perfect time management solution for a drive-thru service.
In the beginning, In-N-Out's menu was fairly simple consisting of single patty hamburgers, French fries, bottled soda, and believe it or not, hot chocolate. A decade in, fountain soda came into the picture (10 cents got you a 12-ounce cup) and it wasn't until the early 1960s that the double-double hamburger and animal-style hamburger became available. Flash forward to 1975, In-N-Out finally announces a dessert will be added to the official menu: milkshakes.
In-N-Out has offered the same three flavors for 46 years.
If you're craving a milkshake mixed with your favorite candy, laced with hot fudge, or topped with whipped cream, then you've come to the wrong place. If you're in the mood for a hamburger with a side of fries that you can dunk in a single-flavored shake, then proceed to the In-N-Out drive-thru. 46 years after it opened, the California fast food chain updated its menu in 1975 to offer vanilla, chocolate, and strawberry milkshakes made with real ice cream (via In-N-Out). However, "select locations" had already been serving malts for almost 10 years before that! So, one could say that In-N-Out already knew shakes would be a home run among customers.
In-N-Out's original menu has gone through very little changes over the years. To this day, the chain continues to only make chocolate, vanilla, or strawberry milkshakes. But according to Serious Eats, there are three additional milkshake options on the In-N-Out secret menu. The first is fairly obvious: Neapolitan, which is a mix of all three flavors. You can also order a "black and white," which is a vanilla chocolate milkshake swirl. Lastly, you can ask for a root beer float. There's no official code for a chocolate-strawberry or vanilla-strawberry milkshake combo, but seeing as In-n-Out has both flavors, such a request doesn't seem too far fetched.