Step 1

Prepare and bake the chocolate cake mix following packet directions. Turn onto a wire rack to cool completely. Use a large serrated knife to cut the cake horizontally into 3 even layers.

Step 2

Drain the cherries, reserving 160ml (2/3 cup) of the juice. Reserve 10 cherries to decorate. Place the remaining cherries and the reserved juice in a saucepan with the sugar and cornflour. Stir over medium-low heat until the mixture boils and thickens. Transfer to a large bowl. Cover with plastic wrap and place in the fridge to chill.

Step 3

Use an electric beater to beat cream in a medium bowl until firm peaks form.

Step 4

Place kirsch, water and extra sugar in a jug and stir until the sugar dissolves.

Step 5

Place 1 cake layer on a serving plate and drizzle over half of the kirsch mixture. Spread with half of the cherry mixture and a thin layer of the cream. Repeat with the remaining cake, kirsch mixture, cherry mixture and cream, finishing with a layer of cake.

Step 6

Spread some of the remaining cream over the top and side of the cake. Sprinkle the chocolate over the top and gently press onto the side of the cake.

Step 7

Place the remaining cream in a piping bag fitted with a 1cm fluted nozzle and pipe rosettes around the edge of the cake.

Step 8

Arrange the reserved cherries around the cake between the cream rosettes. Cut the cake into wedges to serve.