Black Forest log with Morello cherries

Preparation

1. Whip the full cream and mascarpone.
2. Once the whipped cream is almost stiff, add the sugar and vanilla sugar sachets. Whip again and set aside in the fridge.
3. For the sponge cake: separate the egg yolks from the egg whites. Whisk the egg whites until stiff.
4. Add the sugar and whisk again. Add the yolks and beat again.
5. Sift in the flour, baking powder and cocoa. Mix well.
6. On a baking tray lined with baking paper, spread the dough evenly into a rectangle.
7. Bake the biscuit for 8 minutes at 180°C.
8. When the biscuit is cooked, place a damp cloth over it and roll it into a log shape.
9. Drain the Morello cherries and reserve 70g of their syrup. 
10. To make the syrup, heat the water and sugar in a saucepan. Once the sugar has dissolved, add the kirsch off the heat and then the Morello cherry syrup.
11. Soak the biscuit in this syrup with a brush.
12. To assemble the buche: spread a thick layer of the whipped cream (save some for garnishing) over the biscuit, leaving 3 cm on the sides.
13. Spread the Morello cherries (keep a few for garnishing) over the cream and roll up the cake.
14. To serve: spread a thin layer of cream over the whole log. Sprinkle with cocoa powder. Add a few morello cherries. Sprinkle icing sugar over the cherries for a snow effect.