Cake can be assembled up to three hours ahead. Cover loosely with plastic wrap and refrigerate. Decorate just before serving. Kirsch is available from liquor retailers, replace with orange-flavoured liqueur, if preferred.
670g jar pitted morello cherries
¼ cup cherry-flavoured liqueur (Kirsch)
600ml tub thickened cream
180g block black forest milk chocolate, finely chopped,
Extra chopped black forest chocolate, to decorate
½ cup cocoa powder
225g unsalted butter, chopped, at room temperature
1¼ cups caster sugar
1 ½ cups plain flour
½ cup self-raising flour
1 teaspoon bicarbonate of soda
3/4 cup milk
Grease two 20cm round cake pans. Line bases and sides with paper, extending paper 2cm above pan edges.
To make cakes, combine cocoa with 1/2 cup boiling water in a heatproof jug. Whisk until smooth. Cool.
Beat butter and sugar in a large bowl of an electric mixer until light and fluffy. Beat in eggs, one at a time, until combined. Reduce speed to low. Beat in cocoa mixture. (Mixture will look curdled at this stage.)
Fold in combined sifted flours and soda with milk, in two batches. Divide evenly between prepared pans. Smooth over tops.
Cook in a moderately slow oven (160C) for about 35 to 40 minutes, or until a skewer inserted into centre comes out clean. Remove. Stand in pans for 10 minutes. Turn out onto wire racks to cool.
Drain cherries, reserving ¼ cup syrup. Combine reserved syrup with liqueur in a small jug. Set aside 15 cherries for decoration.
Beat cream in small bowl of an electric mixer until soft peaks form. Transfer 1 ½ cups whipped cream to a separate bowl. Refrigerate, covered. Fold chocolate into remaining whipped cream.
Using a large serrated knife, cut cakes horizontally in half. Place one cake layer, cut-side up, on a serving plate. Brush with some of the syrup mixture. Spread with one-third of the chocolate cream. Top with one-third of the remaining cherries. Repeat layering with remaining cakes, syrup mixture, chocolate cream and cherries, finishing with a cake layer. Refrigerate for 30 minutes.
To serve, beat reserved cream until firm peaks form. Spread over top of cake. Decorate with reserved cherries and extra chopped chocolate.