Ingredients

• 225g/8oz plain chocolate
• 4 eggs, separated
• 100g/4oz caster sugar
•   caster sugar, extra for sprinkling
• 300ml/½ pint double cream
• 225g/8oz canned natural chestnut purée
• 4 tbsp icing sugar, sifted
•   icing sugar, extra for dusting
• 1-2 tbsp brandy

Method

1. Preheat the oven to 180C/350F/Gas 4. Line a 23x33cm/9x13in swiss roll tin with greased greaseproof paper. Break 50g/2oz of the chocolate into a heatproof bowl and place over a pan of gently simmering water; stir until melted.
2. Pour the chocolate in a thin layer on to a cold, upturned baking tray; leave to set. Holding a sharp knife at a 45 degree angle, shave the chocolate to form curls. Place on greaseproof paper and set aside.
3. Melt the remaining chocolate as in step 1. Whisk the egg yolks with the caster sugar for 5 minutes until pale and thick; stir in the chocolate. Whisk the egg whites until stiff, then carefully fold into the yolk mixture. Spoon into the tin and spread out evenly, then bake for about 15-20 minutes until risen and firm.
4. Sprinkle a piece of greaseproof paper with caster sugar, then turn out the roulade on to it. Carefully peel off the lining paper, cover with a warm, damp tea towel and cool.
5. Whip the cream until it forms soft peaks. Mix together the chestnut purée, icing sugar and brandy. Gently fold all but five tablespoons of the cream into the chestnut purée mixture using a large metal spoon.
6. Spread the cream mixture over the roulade to within 1cm/½in of the edges. Carefully roll up from one short end, using the paper to help. Swirl over the reserved cream, scatter over the chocolate curls and dust with icing sugar. Chill until ready to serve.

Notes