Cut 16 slits in the top of a weighted egg carton or use a polystyrene square. Line a large baking tray with baking paper.
Break cake into pieces and process in a food processor. Transfer mixture to a large bowl. Roll heaped tbsps of the mixture into 16 balls, then shape into eggs. Place onto the lined tray; cover with plastic wrap and refrigerate for 3 hrs or until firm.
Place chocolate into a microwave-safe bowl, heat in microwave on medium (75 per cent) in 20 sec bursts. Stir occasionally to ensure the chocolate has melted through. Pour chocolate into a small jug ready for dipping.
Stick the end of a lollipop stick into the melted chocolate, push stick about halfway into the ball of cake. This will help the stick and cake to hold together. Return to lined tray.
Dip each cake pop into the melted chocolate, rocking them backwards and forwards to ensure they are well coated to the beginning of the stick. Do not twist as this may loosen the cake from the stick. Remove in one smooth movement, then place stick into the egg carton. Any excess chocolate that dribbles down the stick can be wiped clean. Repeat with remaining cake balls. Stand cake pops until chocolate is set. Re-dip cake pops in chocolate. Stand until set.
Sift icing sugar through a very fine sieve. Lightly beat egg white in a small bowl with an electric mixer; add icing sugar, a tbsp at a time. When the icing reaches firm peaks, use a wooden spoon to beat in juice. Cover tightly with plastic wrap until ready to use.
Divide the icing into several bowls, colour with a few drops of food colouring, then transfer to disposable piping bags. Decorate cake pops with spots, lines, decorative patterns and icing flowers.
TIP Not suitable to freeze. Chocolate suitable to microwave. Lollipop sticks are available from craft stores. Royal icing begins to set as soon as it’s exposed to the air, so keep the icing covered tightly with plastic wrap while you’re not working with it.