Put the white chocolate in a heatproof bowl. Warm the cream in a small saucepan over a medium heat until it steams and just begins to bubble, then pour it over the white chocolate and leave for 1 min.

For the silkiest ganache, use a hand blender to blend the cream and chocolate from the centre of the bowl outwards. (Keep the blender submerged to avoid adding air to the mixture.) If you don’t have a hand blender, whisking from the centre will also work. If you still have lumps of chocolate, gently warm the ganache in the microwave in 5-second bursts, stirring between each until smooth. Leave to cool slightly before using (it should be a spreadable consistency). If it sets too hard, gently warm in the microwave or in a heatproof bowl over simmering water. Will keep chilled for three days or in the freezer for up to a month.