Key Lime Pie Recipe

Preheat the oven to 160°C (140°C fan/Gas Mark 3). Whizz the digestive biscuits into fine crumbs in a food processor, or crush them in a sturdy plastic bag with a rolling pin.

Mix the biscuit crumbs with the melted butter, then press this mixture firmly into the base and up the sides of a 22cm loose-based tart tin. Bake the crust for 10 minutes, then remove it from the oven and let it cool completely.

In a large bowl, whisk the egg yolks with electric beaters for about 1 minute until they lighten slightly. Pour in the condensed milk and continue whisking for another 3 minutes.

Add the lime zest and juice, then whisk for a final 3 minutes until the mixture is thick and pale. Pour this filling into your cooled biscuit base, then return the pie to the oven for 15 minutes. Once baked, let it cool completely on a wire rack before chilling it in the refrigerator for at least 3 hours, or ideally overnight, until it's fully set.

When you're ready to serve, carefully remove the pie from its tin and transfer it to a serving plate. For the topping, softly whip the double cream with the icing sugar until it holds gentle peaks.

Dollop or pipe the whipped cream over the top of the pie, then finish with a scattering of fresh lime zest for a bright flourish.