Easy key lime pie
Melt the butter in a small pan and stir in the crushed biscuits. Lightly press into the base of a 23cm/9in deep loosed-bottomed fluted flan tin. Chill whilst preparing the filling.
To prepare the filling: place the lime juice into a large bowl, add the cream and condensed milk. Whisk for 1-2 minutes. Add the lime zest and lightly stir. Pour onto the prepared biscuit base. Place onto a tray and chill in the fridge for 1-2 hours.
Decorate with crystalized lime zest and serve.
To make the crystalized lime zest, wash and dry 2 whole limes and peel with a vegetable peeler. Using a sharp knife cut the peel into thin matchstick-sized strips. Blanch in boiling water for 1 minute. Drain and refresh in cold water. Place 50g/2oz caster or granulated sugar into a small pan with enough boiling water to cover. Bring to the boil and heat until it reaches 180C/350F, use a sugar thermometer to test the temperature. Add the lime zest and remove from the heat. Stir well and pour into a metal sieve over a bowl. As the sugar cools separate the lime zest with a fork and allow to cool completely. When cool remove the lime zest from the sieve and rub off the excess hard sugar. Use as required in the key lime pie recipe.