My life is all about banging things out, getting things done, moving fast—but sometimes a detour from the fast lane can be a good thing, even for me. Years ago, Gwen and I were on our way home from a road trip to the Canadian Maritimes when we were forced off the highway by some epic construction. We ended up on a wandering road that took us through a charming series of dying industrial towns. There was not much to see... and definitely nothing to eat. But then, in Fall River, Massachusetts, right at the border of Rhode Island, we stumbled across culinary gold: an old gas station converted into a root beer stand. The owner, a retired A&W root beer guy, was behind the counter; all he served was root beer in frosted glasses. Our root beer came with a long lecture about chilling the glass, not the root beer itself (that kills the taste). We hadn't the time to ask his stance on the root beer float. We sat at a broken-down old picnic table and sipped. I'm all about root beer, and that roadside glassful was the best I ever tasted. This recipe is my stab at bringing that taste to cake—because the only thing better than root beer is root beer plus cake.
There's a mad-scientist component to this recipe: when you whisk the baking soda into the molasses and root beer, there's going to be some crazy bubbling up going on, straight out of sci-fi. Don't worry: it's completely normal.
Sassafras is key in the glaze. I buy it at Kalustyan's, the mind-blowingly-good spice shop on lower Lexington Avenue in New York. If your local specialty store doesn't stock it, you'll be able to get it online—I found it on Amazon. You can substitute extract if you can't get your hands on the bark. I also give a substitute for fresh nutmeg here—but if you can find it, the fresh-grated stuff is way better than the powdered kind.
