1. Set the oven to 200 degrees. Grease and line a 33 x 23cm baking tin with baking parchment.
2. Whisk the eggs and sugar together until ribbons form - the mixture will become thick, much like double cream. This will take at least 4 minutes (perhaps more) and the mixture will turn a lovely pale yellow.
3. Sieve the flour and cocoa powder into a separate bowl, then fold into the egg mixture, using a metal spoon. Don't over mix here, you don't want to beat the air out of it. Pour in to the lined tin, making sure it goes into the corners (it should be wonderfully fluffy and full of bubbles).
4. Bake for 8-10 minutes until pale golden, with the sides shrinking away from the edge of the tin. It should bounce back if you press a finger onto the middle.
5. Place a clean tea towel on a kitchen surface and turn out the sponge onto the towel, removing the baking parchment. Whilst the roll is still warm, roll tightly, from the longer edge and leave to cool. This will ‘train’ the sponge for the final roll.
6. Melt the chocolate and 300ml of the cream in a bowl over a pan of simmering water. Refrigerate until cool and thickened. Whip the remaining double cream into soft peaks and put into a piping bag with a star tip.
7. To assemble the roll, spread the chocolate icing with a layer of cream and as many cherries as you can muster (don’t overfill or it won’t roll). Make sure you leave a 2cm gap around the edges. Reroll the sponge and don’t worry if the filling spills from the sides – you can correct this whilst decorating.
8. Place the roll on the dish on which you intend to serve it. Then spread the chocolate icing into the roll, using a palette knife for a smoothish finish.
9. Pipe on the cream to the chocolate, making little cream ‘kisses’ in lines across the sponge. Adorn with as many cherries as you see fit and demolish those that remain because they are utterly delicious.