For convenience, you can make the undipped cake balls up to 2 days ahead and store them in the fridge. Candy melts: When melting candy for decorating, do so slowly in a microwave-safe bowl at 50% ...

Beat in vanilla and a pinch of salt. Crumble cake into frosting and mix to combine. Form into 1 1/2" balls (about 34 total). Arrange on a baking sheet and refrigerate until firm, about 1 hour.