Fast-food chains like Sonic spend months inventing and testing craveable creations before they hit the menu.

We visited Sonic's test kitchen inside its headquarters in Oklahoma City to get an inside look at how the hot dogs get made.

Sonic's chef, Scott Uehlein, fed us new and upcoming menu items, from a pickle juice slush to a Philly cheesesteak on a hot-dog bun with Baja sauce.

The idea of putting pickle juice in a slushie seems like a fever dream of a brine-obsessed mad scientist. However, for Scott Uehlein, it's just another day of work.

Uehlein is Sonic's vice president of product innovation and development. He spends his days conceptualizing, creating, and testing new creations that might one day find a spot on the menu at the fast-food chain — like the pickle juice slush, which hit menus in June.

On a recent trip to Oklahoma City, we had a chance to stop by Sonic's headquarters. And, while we were there, we dined on a full — perhaps overstuffed — menu of new and upcoming creations from the fast-food chain's test kitchen: