The classic root beer float only has two ingredients — root beer and vanilla ice cream — but the ultimate root beer float has four, elevating it to root beer float stardom with whipped cream, cherries… and a splash of booze. Of course, you can omit the alcohol, if desired.
Freeze the glasses and root beer for 10 to 20 minutes. Then, add 1 cup of the ice cream to each glass. If you are using the vanilla vodka or bourbon, add now. Next, slowly add root beer, pouring at an angle. Finally, top your root beer float with whipped cream and maraschino cherries.