Method

Heat the oven to 180C/fan 160C/gas 4. Melt the butter in a pan, remove from the heat and stir in the crushed biscuits.

Press the mixture into the base of a 23cm flan dish. Bake in the oven for 10 mins. Remove and cool.

Whisk the egg yolks and lime zest together until pale and thick. Add the condensed milk and whisk for 3 mins, then whisk in the lime juice.

Pour the filling into the cooled base then bake for 15-20 mins until the filling is just set.

Leave to cool, then chill in the fridge for at least 3 hrs or until ready to serve.

Carefully remove the pie from the tin and place on a serving plate. Decorate with lime slices if you like.