Step 1

For the basic chocolate cake, preheat the oven to 160C. Grease and line a 24cm round springform cake pan.

Step 2

Sift the flour, cocoa, baking powder and bicarbonate of soda into a bowl. Set aside.

Step 3

Melt the chocolate in a heatproof bowl set over a pan of barely simmering water (don't let bowl touch water). Cool slightly.

Step 4

Beat butter and sugar with an electric mixer until light and fluffy. With beaters on medium speed, add vanilla, then add eggs, 1 at a time, beating well after each addition. Pour in cooled chocolate and beat until well combined. Beat in a third of sifted ingredients, followed by a third of the milk. Repeat until all ingredients are incorporated, beating until smooth.

Step 5

Pour mixture into the pan and bake for 45-55 minutes until risen and a skewer inserted in the centre comes out clean. Cool in the pan on a rack for 10 minutes, then invert onto rack to cool completely.

Step 6

Combine cornflour with 2 tablespoons of the reserved cherry juice. Place remaining juice in a pan with sugar over medium-low heat and stir for 2 minutes to dissolve sugar. Add cornflour mixture and stir for 1-2 minutes until sauce thickens. Stir in the cherries and kirsch, then remove from heat and cool. Chill until needed.

Step 7

For the custard, heat milk and cream in a pan over medium heat to just below boiling point. Remove from heat. Whisk egg yolks and sugar in a bowl until well combined. Gradually whisk hot milk mixture into yolk mixture. Return to a clean pan over medium-low heat. With a wooden spoon, stir gently but constantly, for 4-5 minutes, reaching the base and corners, until the custard is thick enough to coat the back of a spoon (when you run a finger along the spoon, it should leave a trail). Remove from the heat. Strain through a fine sieve into a container. Cool for 15 minutes, stirring occasionally. Stir in the jam, cover and chill.

Step 8

Whip the cream with the icing sugar to soft peaks. Slice cake horizontally into 3 even rounds. Place 1 cake layer in a 2-litre serving bowl, trimming to fit if necessary. Spread with half the custard, then top with one-third of the cherry mixture. Repeat this process, then top with the final layer of cake. Top with the whipped cream, then arrange the remaining cherries on top. Chill for at least 2 hours for flavours to develop, then serve garnished with grated chocolate.