In a large bowl, mix confectioners' sugar and cocoa until blended. Add crushed wafers and walnuts; toss to combine. In another bowl, mix corn syrup and rum; stir into wafer mixture.
Shape into 1-in. balls. Roll in additional confectioners' sugar. Store in an airtight container.
Rum Balls Tips
What kind of rum should you use to make rum balls?
Most recipes call for some kind of spiced or dark rum, which will give the rum balls warmth and depth of flavor. No matter what kind of rum you choose, though, make sure you love the flavor because it will shine through in every bite. Need a recommendation? Our Test Kitchen tested different Jamaican rum brands.
How can you make rum balls your own?
Although rolling rum balls in additional confectioners' sugar is definitely delicious, one easy way to make them your own is by switching up the coating. Some other toppings options include shredded coconut, cocoa powder, sprinkles or crushed nuts.