This roulade is light and zingy with fresh lemon flavours. If you have the time, making your own lemon curd will make it even more delicious. It works both as an afternoon-tea cake or as a dessert. You will probably have a little mousse left over which could be served with the roulade or just treated as the cook’s perks!
SERVES 8
For the mousse
220g good-quality white chocolate
1½ leaves of gelatine, soaked in cold water
130ml double cream
210ml double cream mixed with 1½ tbsp semi-skimmed milk, whipped to very soft peaks
For the sponge
3 large free-range eggs, separated
85g icing sugar, sifted
1 lemon, zest only
25g cornflour
25g soft pastry flour
2 tsp caster sugar
To serve
120g lemon curd
6 green pistachios
white chocolate shavings
1. Preheat the oven to 160°C.
2. To make the mousse, melt the chocolate in a heatproof bowl either on a low setting in the microwave or over a pan of gently simmering water. Soak the gelatine in cold water.
3. Bring the 130ml of cream to a simmer, remove from the heat and add the soaked gelatine, stirring well to thoroughly dissolve. Gently whisk this into the white chocolate to form a ganache.
4. Check that the temperature of the ganache is around 35–40°C and then fold in the whipped cream/milk mix. Pour into a plastic container and allow to set in the fridge for at least 2 hours.
5. For the sponge, whisk the yolks with two-thirds of the sugar until thick and pale. In a separate bowl, whisk the whites to soft peaks and then whisk in the remaining sugar. Continue to whisk until a thick, glossy meringue is formed.
6. Stir one-third of the meringue into the yolk mix and then gently fold in the remainder using the whisk. When three-quarters mixed, grate the lemon zest over the top, then sift in the flours and continue to fold together until just incorporated.
7. Line a Swiss roll tin with baking parchment and then lightly butter and flour. Pour the sponge mix into the tin and level with a palette knife. Bake for 8–10 minutes until risen, firm and golden. Sprinkle with caster sugar and immediately invert onto a sheet of baking parchment. Remove the lining paper, trim the edges of the sponge and roll up with the paper into the classic roulade shape. Allow to cool.
8. To assemble, unroll the cooled sponge and, with a palette knife, spread the lemon curd over the inside surface, keeping a 2cm margin around the edges. Top the lemon curd with three-quarters of the white chocolate mousse, working from the centre to the outside edges. Roll the roulade up and position with the seam at the bottom. Use the remaining mousse to spread a thin layer over the roulade. Shave curls off the back of the chocolate bar by pulling a heavy cook’s knife towards you at an angle of about 30 degrees. Scatter the chocolate shavings over the soft mousse on the roulade and then, with a fine grater, grate some pistachio over the top. Chill the roulade for 4-5 hours to set firmly, removing from the fridge 1 hour before serving.