Have ready a sheet pan lined with wax paper or a large food storage container, plus a few sheets of wax paper (to be used for separating layers) -- whichever will fit best in your freezer.

Once the cake has cooled, transfer it to a large mixing bowl in large chunks and break up into crumbles with your hands.

Add the frosting, vanilla, salt, and sprinkles if using, and either mix with your hands or a sturdy wooden spoon until well-combined.

With cupped hands, roll about 2 tablespoons of the mix into a ball. Taper the top to look like an egg, and set on the wax paper. Repeat until all of the mix has been prepared.

Transfer all of the cake balls to a sheet pan lined with wax paper or the storage container. If using the storage container, separate each layer of cake balls with a sheet of wax paper. Freeze for 1 hour.

Combine Jimmie and nonpareils sprinkles in a bowl and mix to combine. Set aside until ready to use.

Remove from the freezer, and melt the candy wafers according to package instructions. If you'd like, transfer some of the melted wafers to a Pyrex measuring cup to make dipping easier.

Submerge the cake ball completely in the melting wafers, and allow the excess to drip off before transferring to the work surface.

Decorate the cake ball with sprinkles right away, before the coating hardens. Repeat with the remaining cake balls.

Allow the candy shell to harden completely before serving, 25-30 minutes.