Pistachio ganache

Makes: about 650 g (1 lb 7 oz) to fill and cover one 18 cm (7 in) round cake

Preparation time: 15 minutes

Cooking time: 5 minutes

Chilling time: at least 1 hour

300 g (10½ oz) white chocolate, broken into pieces

60 g (2¼ oz) unsalted pistachios, shelled

1–2 drops almond extract

300 ml (10½ fl oz) thick (double) cream

Put the chocolate in a heatproof bowl set over, but not touching, a saucepan of gently simmering water, and stir occasionally, until melted, about 5 minutes. Meanwhile, grind the pistachios and almond extract together very finely using a food processor until a thick paste forms. Put the paste in a saucepan, add the cream and bring just to the boil. Remove the bowl of melted chocolate from the heat, pour the warm cream over it and stir until well combined. Cover with plastic wrap and chill immediately in the refrigerator for at least 1 hour before using.