In a food processor, blitz the cake and juice to fine, moist crumbs. Put in a bowl and chill in the fridge for 30 minutes. Line a baking tray with baking parchment.
Roll the chilled mixture into 12 compact balls. Melt the chocolate in a bowl set over a pan of simmering water (the bowl shouldn’t touch the water).
Remove the pan and bowl from the heat. Dip the tip of each cake pop stick into the melted chocolate, then push into a cake ball. Place on the lined baking tray and freeze for 30 minutes. Sit the bowl of chocolate over the pan of warm water (off the heat) to prevent it from setting.
Remove the cake pops from the freezer. Drizzle a cake pop with melted chocolate, turning as you spoon it over and allowing the excess to drip off. Scatter straight away with sprinkles, as the cake pop will set quickly. Stand upright in a glass or cup to set completely. Repeat with the remaining cake pops, then chill until you’re ready to eat or pack up as gifts.