• Preheat oven to 350°F. Lightly grease a 9x13-inch baking pan and line with parchment paper, leaving an overhang for easier removal. Line a baking sheet with parchment paper and set aside.

Prepare The Cake:

• Prepare the cake mix as directed on the package. Pour the batter into the prepared pan and bake fully per package directions—typically 25-30 minutes, or until a toothpick inserted in the center comes out clean or with just a few moist crumbs.
  
• Transfer to a wire rack and let the cake cool completely in the pan, about 45 minutes.
  

Make And Chill The Cake Balls:

• Once cooled, crumble the cake into fine crumbs in a large mixing bowl, being careful to break up any large clumps.
• Add about 1/2 cup of the vanilla frosting to the cake crumbs.
  
• Using a spatula or clean hands, mix until the mixture holds together when pressed. If it feels dry or crumbly, mix in additional frosting, 1 tablespoon at a time, until it forms a dough that’s moist but not sticky.
  
• Using a small cookie scoop or two tablespoons, portion the dough into 25 equal-sized mounds, about 1 1/2 inches each. Roll each portion between your palms into a smooth ball and place them on the prepared baking sheet, spacing them evenly so they don’t touch.
  
• Refrigerate the cake balls for at least 1 hour to firm up, or freeze for 15-20 minutes, until firm but not frozen solid.

Assemble And Finish The Dish:

• In a microwave-safe bowl, heat the candy melts on 50% power in 30-second increments, stirring between each, until smooth. Thin with a teaspoon of shortening or coconut oil if the coating seems too thick.
• If using, place the sprinkles in a shallow bowl.
• Dip the tip of a lollipop stick about a half inch into the melted candy, then insert it halfway into a cake ball. The melted candy helps secure the stick.
  
• Holding the stick, dip the entire cake ball into the melted candy. Gently turn to coat evenly, then tap the stick lightly on the edge of the bowl to remove excess coating.
  
• While the coating is still wet, roll or sprinkle with decorations, if desired.
  
• Stand each cake pop upright in a cake pop stand, styrofoam block, or a small container filled with uncooked rice or sugar. Let stand until the coating is fully set and hardened, about 30 minutes at room temperature or 15 minutes in the refrigerator.
• Serve right away or cover and refrigerate.