Crumble the cooled cake into a large bowl, leaving no large chunks of cake.
Add the frosting to the bowl and, using a rubber spatula, fold and stir in the frosting until it has evenly coated all of the cake crumbs.
Use a small cookie scoop (or 1 tablespoon) to scoop out the cake mixture and roll into a ball; place on a lined baking sheet.
Cover with plastic wrap and refrigerate until firm, 2 to 3 hours. At this point, you can smooth out the balls, if you’d like. If you do so, return them to the refrigerator for at least 30 minutes.
Melt the coating in a tall cup (a 2-cup measuring cup or mason jar works well for this!). If using melting wafers, follow the melting instructions on the package. If using chocolate, combine the chocolate and vegetable shortening and microwave on 50% power, stirring every 30 seconds, until completely melted and smooth.
Work with only a few cake balls at a time and leave the remainder in the refrigerator.
Dip a lollipop stick about ½ inch into the melted coating, then insert about halfway into a cake ball.
Dip the cake ball the entire way into the melted coating, ensuring that the coating meets the coating on the lollipop stick, which will secure the cake pop.
Allow excess coating to drip off (at this point you can decorate with sprinkles, if desired), then insert the cake pop upright in a styrofoam block. Allow to set completely (about 1 hour at room temperature) before removing.