Direction :

1. Place vanilla wafers in a food processor and pulse into fine crumbs. There might be a few large pieces that don’t catch the blade at this step, but they’ll eventually end up getting pulverized, so don’t worry. (Alternatively, place vanilla wafers into a Ziploc bag and bash them with a rolling pin until they are fine pieces).
2. Add confectioners’ sugar, cocoa and corn syrup and pulse till combined. Add the 1/3 cup rum and pulse to combine. If necessary, slowly add more rum to the food processor until the mixture comes together and forms a mass around the blade or holds together when you pinch it. 
3. Using a teaspoon or a #100 scoop, scoop out balls from the processor, roll them gently with your hands to form balls, then drop them onto a plate (or shallow tupperware) filled with a thin layer of powdered sugar. Shake the vessel to coat the balls, then transfer the balls to an airtight storage container until you are ready to serve them. Store at room temperature for up to a week or freeze for up to 3 months. Bring to room temperature briefly before serving.