Not really Key Lime, but that's what it's mostly called (key limes are quite large and yellow - the ones we get in the UK
are small and green, generally the Persian lime, but the taste is much the same). This is how I made the pie...
Pulverise 200g plain chocolate digestive biscuits in a food processor, mix in 75g melted butter and press into a 22cm
loose-bottomed tart tin. Bake for 10 minutes in a 170°C oven to set, then let cool. Beat 3 large egg yolks until pale
and creamy then add a 400g can of condensed milk. Beat for another 3 minutes, then add the finely grated zest and juice
from 4 limes. Beat for another 3 minutes then pour into the biscuit crumb crust and bake in the oven for 20 minutes, until set.
Let cool, chill before serving with a dollop of crème fraîche.