Yule-log fires and silken frocks

When we were small my grandma used to make a Yule log for us to eat at Christmas tea. I've taken up the tradition. I made it so i can freeze it in preparation for the big day. I've even got grandma's Yule log box to keep it in.
Unfortunately her recipe has vanished but nigella's is close:
For the cake:
6 eggs
150g caster sugar
50g cocoa powder
1 teaspoon vanilla extract
3-5 teaspoons icing sugar

For the icing:
175g dark chocolate
250g icing sugar
225g soft butter
1 tablespoon vanilla extract

Preheat oven to 180°C / gas mark 4

1. Whisk egg whites into peaks. (as if making a meringue) Add 50g of sugar.
2. In a separate bowl whisk the yolks and rest of sugar so it is pale and thick. Add vanilla and seive in cocoa.

3. Fold in yolks a couple of dollops at time. FOLD -DO NOT OVERBEAT.

4. Pour into a lined swiss roll tin (line with baking parchment and leave edges overhanging).

5. Bake for 20 minutes.

6. Let it cool a little before turning it out on to more baking parchment. Remove original baking parchment.

For icing
1. Add butter to icing sugar (use food processor of you have one). Mix until well blended.
2. Add the melted, cooled chocolate and vanilla.
3. Mix until smooth

Putting it together
1. Lightly spread icing over the sponge
2. Roll away from you (from longest side) until it is tightly rolled.
3. Decorate with remaining icing so fully covered. Use a fork to make lines.

I've frozen mine and will sprinkle icing sugar over it in Christmas day. You can freeze it for up to 3 months or keep it in a sealed, airtight container for a week.

The recipe is available here: http://www.nigella.com/recipes/view/yule-log