Cake: Preheat the oven to 180 degrees C. Line the bottom of a deep 23cm round cake tin with greaseproof paper.
Sift the flour, cocoa powder and half the caster sugar into a medium bowl.
Place the egg whites in a large bowl and beat with an electric mixer until they form soft peaks. Gradually add the remaining sugar, 1 tablespoon at a time, then the vanilla essence. Beat until the egg whites are glossy, smooth and form firm peaks.
Sprinkle the flour and cocoa mixture over the egg whites and fold in gently but thoroughly with a metal spoon, taking care not to deflate the egg whites too much. Spoon the mixture into the prepared tin. Smooth the surface gently. Sprinkle the cherries evenly over the top of the cake.
Bake for 20–25 minutes or until the cake has risen and is just firm to the touch yet still moist on top. A skewer inserted in the centre should come out clean. Remove from the oven and leave to cool.
To Serve: Dust with icing sugar to decorate. Mix together thickened cream, cherry conserve and kirsch to taste then serve with the cake.