Always on the look out for ideas to use up the significant quantities of egg yolks that are a natural and unavoidable “waste” product of macaron-making, I recently hit upon Key lime pie. This rather indulgent creamy dessert originated in Florida Keys, where they grow the Key lime, a citrus fruit which although yellow once ripe, is usually picked when still green. The Key lime is small and quite acidic, tart and bitter giving the original Key lime pie a unique flavour. However, I have been delighted with the results achieved using the standard limes available in local supermarkets and greengrocers. An instant success with family and friends of all ages – and very simple to make, I would certainly recommend this recipe.
For the base:
100g (3.5oz) unsalted butter
225g (8oz) digestive biscuits (chocolate ones would add to the indulgence!)
For the creamy filling:
Juice of 5 limes – and zest of 3 of the limes
An extra lime for decorating – optional
4 medium egg yolks
400g can of condensed milk
- Crush the biscuits in a strong plastic bag with a rolling pin, or whizz them to crumbs in a food processor. Melt the butter in a saucepan over a low heat. Add the biscuit crumbs and stir until well combined. ( it is possible to add aster sugar to this mixture but it seems superfluous to me – and only adds more calories! Tip the mixture into a 22cm (9in) loose-based flan tin, or into a fluted pie dish and press it firmly into the base and up the sides, using a metal spoon. Place the tin on a baking tray – not necessary if using a pie dish – and bake in the oven at 180 C (350 F/Gas 4) for 10 minutes. Let it cool and settle before filling.
- While the pie base is cooking and cooling, prepare the filling. Grate the zest of 3 of the limes, taking care not to grate the pith. Juice all 5 limes and set the juice aside.
- Whisk the egg yolks in a bowl with the lime zest, until the eggs are thick and creamy. Add the condensed milk and keep whisking , preferably with an electric whisk, for about 5 minutes. If you use a hand whisk, continue for a further 2 minutes, until the mixture is thick and smooth. Add the lime juice and whisk it in until fully incorporated. Pour the creamy mixture into the biscuit case in the tin or pie dish and bake in the oven for approximately 15 minutes, until it is set and firm to the touch. Take care not to over cook or brown the filling.
- Remove the pie from the oven and leave to cool completely. It is best left for 3 or 4 hours in the fridge or even overnight. If you have used a loose-bottom tin, carefully remove the pie and place on a serving plate. Decorate with grated dark chocolate or chocolate curls and lime slices and serve with pouring cream.
- Key lime pie freezes well. Leave to cool, open freeze (undecorated) and when frozen wrap in cling film to protect it until required, up to 2 weeks. Remove from freezer 3 or 4 hours before serving. Decorate.
- As a variation on the traditional Key lime pie, add a meringue topping (as in lemon meringue pie) before baking. ( Obviously that would defeat the object of using up the egg yolks left over from macaron baking – so I’ll just stick with the traditional!)