Key lime pie

Method

1. Heat the oven to 170°C conventional and grease a 23 cm pie dish.
2. For the crust, roughly break up the digestive biscuits and blitz in a food processor until finely ground.
3. With the motor running, slowly pour in the melted butter.
4. Press the mixture into the base and neatly up the side of the pie dish, using the ball of your hand or a tablespoon to flatten and compress it.
5. Bake for about 20 minutes, until deep golden and firm. Set aside to cool completely, then turn the oven down to 150°C conventional.
6. Put the egg yolks, condensed milk and lime juice and zest in a glass bowl and mix gently with a balloon whisk until very well incorporated. The mixture will thicken naturally.
7. Pour into the cold crust and bake for 20–30 minutes, until firm to the touch but still very slightly soft in the centre (not wobbly!).
8. Leave to cool completely, then cover and refrigerate for at least 1 hour, or overnight if possible.
9. To serve, whip the cream with a handheld electric whisk until soft peaks form, then spread over the pie and decorate with a little lime zest.