2 eggs
3 oz sugar
3 oz flour, either self-raising or, if that isn't available, add
1 tsp baking powder when sifting.
Warmed jam
8 oz chestnuts, peeled
3 oz sugar
4 tbls water
1 tbl unsweetened cocoa powder
Grease a 12" by 8" (roughly!) baking tray, and line with baking parchment. Turn the oven to Mark 6, 400F, 200C to get thoroughly to temperature. Whisk eggs and sugar with an electric whisk until white, stiff and foamy. Fold in sifted flour and mix thoroughly. Pour batter on to baking tray and bake for 7-10 minutes, until springy. Turn out at once on to a piece of greaseproof paper, spread with warmed jam, and roll up firmly. Cut a tiny slice off either end to make it tidy (eat these, or discard them!). You can cut a slice off the end and place it in the middle of the cake, to make it look like a branching log, if you like, but it's a bit twee! I did, though!
For the icing, boil the chestnuts until soft, about 10 minutes or less. Boil the sugar and water together until a drop sets instantly in cold water. Puree the chestnuts and the syrup together, and add the cocoa powder. Cover the cake with this, and rough up the back with a fork, so that it sort of looks like bark. If you really want to be twee, you stick a plastic robin in this, and sprinkle with icing sugar to look like frost!