Boozy chocolate and cherry trifle

Method

1. To make the Swiss roll, preheat the oven to 200°C/fan180°C/gas 6. Lightly grease a 26cm x 38cm Swiss roll tin and line with baking paper. Mix the flour, baking powder and cocoa in a bowl and set aside. Whisk the eggs and sugar in a large bowl with an electric hand whisk for 10 minutes until pale and frothy. When the whisk is lifted, it should drip a clear trail across the surface of the mixture.
2. Sift the chocolate flour mixture onto the whisked eggs and carefully fold together with a large metal spoon. Spoon into the prepared tin and level the surface. Bake for 12-15 minutes until the edges have slightly shrunk away from the sides and the sponge is slightly springy to touch.
3. Place a damp tea towel on the work surface, top with a sheet of baking paper, and scatter with a little caster sugar. Turn out the Swiss roll onto it, and carefully remove the lining paper. With a rolling pin, gently roll over the Swiss roll to flatten slightly. While still warm, roll and cover with a damp tea towel to cool and set the shape.
4. Drain the cherries, reserving the Kirsch. Whip 300ml double cream with the vanilla seeds and 2 tbsp reserved Kirsch until softly whipped (this will make the cream pink – use pure Kirsch for white cream, as in the picture). Once the roll is cool, unroll, sprinkle the inside with 2 tbsp more of Kirsch, then spread with the whipped cream. Roll up again, wrap tightly in cling film and chill until ready to use.
5. Line a 2-litre glass bowl with cling film, leaving 3-4cm hanging over the top. Thinly slice the Swiss roll and neatly place slices to cover the whole of the inside of the bowl. Save about 6 slices to use for the trifle base.
6. For the chocolate ganache, melt the chocolate in a bowl over a pan of simmering water with 200ml double cream, then set aside to cool slightly. Cover the Swiss roll slices in the bowl with a thick layer of ganache (use two-thirds). Chill for 30 minutes.
7. Push the cherries into the ganache in an even layer. Whip the remaining cream to soft peaks, then whisk in 2 tbsp Kirsch and the custard, and whip again until firm. Fill the bowl with the whipped cream mix, then cover with the rest of the chocolate ganache and top with the reserved Swiss roll. Fold over the cling film and chill for a few hours, or ideally overnight. When ready to serve, turn out the trifle onto a cake stand and decorate with large chocolate curls.