Bake a cake using your preferred recipe or boxed mix; cool completely.
Crumble the cooled cake finely in a large bowl until no large chunks remain.
Add 3/4 cup frosting to the crumbs and mix until a dough-like consistency forms; add more frosting if needed.
Scoop uniform portions (about 1–1.5 tablespoons) and roll into smooth balls with slightly damp hands.
Place rolled balls on a parchment-lined tray and chill for at least 30 minutes (or freeze 10–15 minutes) to firm up.
Melt chocolate or candy melts in a microwave-safe bowl in 20–30 second bursts, stirring until smooth; stir in shortening if necessary to thin.
Dip the tip of a lollipop stick into melted chocolate, then insert halfway into each chilled cake ball to secure the stick.
Holding the stick, dip each cake ball into the melted coating to fully cover; let excess drip off.
Immediately decorate with sprinkles or nuts before the coating sets, then place upright in a stand or on parchment to finish setting.
Allow the coating to set completely at room temperature or in the refrigerator before serving or packaging.