Make cupcakes. Prepare batter following recipe directions. Bake and cool cupcakes.
Pipe swirl on cupcakes. Prepare buttercream icing following recipe directions. Use tip 2A, a cut disposable decorating bag and icing to pipe a swirl on top of cupcakes. Freeze until firm, about 30 minutes.
Dip cupcakes. Melt bright white Candy Melts candy in microwave-safe bowl according to package directions. Holding cupcake by baking cup, dip icing swirl completely in melted candy. Lift cupcake straight up and out of melted candy. Immediately sprinkle with nonpareils. Chill until set, about 10 to 15 minutes. Reserve remaining candy.
Decorate cupcakes. Use reserved melted bright white candy to attach icing decoration to top of cupcake. Chill until set, about 3 to 5 minutes.