Key lime pie

Method

1. Heat the oven to 170C/150C fan/gas 3 1/2. In a food processor, whizz the biscuits to fine crumbs. Pour the melted butter over the biscuits and whizz again briefly.
2. Press the biscuit mixture into the bottom of the tin and chill for 20 minutes (see Make Ahead).
3. In a large bowl, use a balloon whisk to mix the egg yolks with the condensed milk, 300ml double cream, 5 zested limes and juice of 7 limes until smooth. Pour over the chilled base.
4. Put the tin on a baking sheet and bake for 17-18 minutes until the filling has set with a slight wobble. Cool, then chill for 2 hours or until ready to serve (see Make Ahead).
5. To serve, put the sugar, remaining cream, most of the zest and remaining juice into a large bowl and use an electric hand mixer to beat to soft peaks. Dollop the cream in the centre of the pie and garnish with remaining zest, fresh mint sprigs or raspberries. Either chill until ready to serve or eat straight away.