Raspberry and white chocolate Swiss roll

Ingredients

For the sponge

• 80g/2.oz plain flour
• Pinch of salt
• 3 eggs
• 80g/2.oz caster sugar
• 1/2 tsp vanilla extract
• 1 tbsp warm water
• 35–40 raspberries, defrosted if frozen
• Caster sugar, for sprinkling

For the white chocolate ganache

• 65ml/2fl oz double cream
• 150g/5oz white chocolate

For the filling and decoration

• 150g/5oz raspberry jam
• Icing sugar, to dust

You will need 1 × Swiss roll tin, 20 × 30cm/8 × 12in, greased, base-lined, base and sides dusted with flour.

Method

This Swiss roll is studded with raspberries, giving it a polka-dot pattern. By using preserved raspberries – frozen or in jam form – it is possible to have a taste of summer even in the depths of winter. Usually a Swiss roll is turned out of the tin and then rolled, meaning the top of the sponge in the tin becomes the outside of the roll. Here the polka-dot pattern is usually better on the bottom of the sponge, so it needs flipping over once it is turned out, but omit this stage if the top of the sponge looks good.

For the sponge

Preheat the oven to 170°C/325°F/gas mark 3.

Mix the flour and salt together and set aside. Whisk the eggs and sugar together until they hold their shape and are very light and fluffy (they will approximately quadruple in volume).

Add the vanilla extract and water, then sift in the flour and salt mixture. Using a large metal spoon, fold into a smooth batter, maintaining as much air in the mix as possible. Pour the batter into the tin. 

Stud raspberries into the mix (pointy end downwards), setting them in lines angled at about 30° to one of the long sides. Bake for 12–15 minutes until the sponge is firm to the touch and lightly browned.

While it is baking, liberally sprinkle a large piece of baking paper with caster sugar. Remove the sponge from the oven and turn it out on to the sugared paper, and very carefully peel off the base liner by tearing a strip off at a time. If you want the underside as the roll’s outside, sprinkle the exposed sponge with more caster sugar and immediately cover with another piece of baking paper.

Holding the two sheets together tightly, flip the sponge over. Score a line through the sponge along one of the shorter sides, about 1cm/.in from the edge, then starting from this end roll up the sponge as tightly as possible. 

Leave to cool, rolled and wrapped in the paper, on a wire rack.

For the ganache

Bring the cream to just under the boil in a small saucepan over a medium heat, then pour it over the chocolate. Stir until melted and smooth, then set aside to cool to a spreading, but not runny, consistency.

To assemble

Unroll the cooled sponge, spread with the jam, then ganache, and reroll. Dust very lightly with icing sugar – do not obscure the spots! – and serve.

Grow Your Own Cake by Holly Farrell is published by Frances Lincoln, £16.99. Photography by Jason Ingram.

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