Ingredients

Step by step

1. Preheat the oven to 200°C, fan 180°C, gas 6 and grease and line a large Swiss roll tin (about 26cm x 38cm) with baking paper. Put the eggs and 150g golden caster sugar in a free-standing mixer or large bowl and whisk for 6-8 minutes, or until tripled in size. The mixture should leave a ribbon trail when you lift the whisk out. Sift the flour and mixed spice together and slowly fold this through the mixture, taking care not to knock too much air out. Pour into the prepared tray, smoothing to ensure it reaches all the corners and is level. Bake for 10-12 minutes, or until the sponge feels springy to the touch.
2. Lay another sheet of baking paper on your work surface and sprinkle with the extra tablespoon of caster sugar. When the sponge is cooked, turn it out on the sugar-dusted paper. Carefully peel the lining paper off the base of the sponge, then gently roll up the sponge with the baking paper inside and leave to cool completely.
3. To make the filling, melt the white chocolate in a heatproof bowl set over a pan of barely simmering water, then remove and leave to cool. Loosen the chestnut purée with 2 tablespoons of the liqueur and add the icing sugar. Whip the double cream to soft peaks. Fold a couple of tablespoons of the whipped cream through the white chocolate to loosen it and then fold the remaining white chocolate through the cream.
4. Unroll the sponge and spread the surface with the chestnut purée, then drizzle over the remaining liqueur. Top with the white chocolate cream and spread out, leaving a slight border all around as the cream will squidge to the edges as it is rolled up. Carefully roll up the filled sponge and place on a serving plate, with the seam on the underside. Chill while you make the meringue.
5. For the meringue, put the sugar in a pan with 75ml of water and heat gently until the sugar has dissolved. Bring to a simmer and cook until the sugar reaches 117°C, at which point start whisking the egg whites in a large bowl or stand mixer. When the syrup reaches 120°C, remove from the heat and slowly pour it into the whisking egg whites, avoiding the whisk. Continue to beat for around 5-6 minutes as it cools, until you have a stiff, smooth, glossy meringue.
6. Cover the log all over with the meringue, peaking it to look like bark using a palette knife, or for a more finely grained appearance use a closed-tip star nozzle and piping bag. Using a cook’s blowtorch, toast the peaks of the meringue all over to give a snow-covered log effect.