This can be made up to 1 month in advance and kept in an airtight container in the freezer until needed.
- Rapeseed oil, for greasing
- 100g (4oz) caster sugar
- 5 egg yolks
- 600ml (1 pint) cream
- 250g peanut butter
- Line a 1kg (2¼lb) loaf tin with oiled clingfilm. Place the sugar and 100ml (3½fl oz) water in a heavy-based pan and simmer gently until the sugar has dissolved. Bring to the boil, then continue to boil without stirring until the mixture has reached 116°C (240°F), or the 'soft ball' stage. That means that when you drop a bit of it into cold water to cool it down, it will form a soft ball.
- Meanwhile, whisk the egg yolks in a separate bowl until they look pale yellow in colour and have become thick and creamy in consistency. When the sugar has reached the correct temperature, quickly whisk it into the egg yolks and continue to whisk until the mixture is cold.
- Pour the cream into another bowl and whisk until it forms soft peaks. Mix the peanut butter into the cooled egg yolk mixture and gently fold in the cream. Pour into the lined loaf tin, then cover with clingfilm and freeze for at least 4 hours, or preferably overnight, until solid.
- To serve, carefully remove the parfait from the tin and peel away the clingfilm. Using a sharp knife dipped in boiling water, cut into slices and arrange on plates.
- Cook Ahead: This can be made up to 1 month in advance and kept in an airtight container in the freezer until needed.