Rainbow yule log

Heat oven to 180C /160C fan/gas 4. Grease and line a 23cm x 33cm Swiss roll tin with baking parchment.

Beat together the eggs and caster sugar with an electric hand whisk until pale, thick and doubled in volume. Working quickly, divide between 6 bowls and stir a colouring paste into each portion.

Sift the flour and baking powder into a separate bowl and combine evenly. Sprinkle 3 tbsp of the flour mixture over each portion of the egg mixture. Drizzle with a little of the melted butter. Fold together very gently, taking care not to knock out the air.

Gently spoon each mixture into separate piping bags, then cut off each tip to create a 2cm hole. Pipe lines of the mixture diagonally across the Swiss roll tin in a rainbow pattern, making sure the lines touch each other. Continue until the tin is full and the mixture is used up. Bake for 12 mins, or until springy and dry to the touch.

Place a large piece of baking parchment onto a clean surface and sprinkle with caster sugar, then turn the cake out onto it. Remove the lining paper and loosely roll up the sponge from the short side, with the sugared paper rolling along with it. Cover with a damp tea towel and leave on a wire rack to cool completely.

For the whipped cream filling, beat the cream with an electric hand whisk until soft peaks form. Add the icing sugar and vanilla extract and whisk briefly until just combined.

Gently unroll the cake and remove the paper. Spread the cream filling evenly across and reroll. Trim the ends if any cream leaks. Dust with icing sugar before serving.