Put the digestive biscuits into a bag and crush with a rolling pin.
Melt the butter in a saucepan over a gentle heat. Gradually stir in the crushed digestive biscuits. When fully mixed press the mixture into a 7inch loose bottom cake tin. Chill in the fridge for 30 minutes.
Spoon on the Lime Curd on the biscuit base. Whisk the double cream in a bowl until it forms soft peaks. Spoon this on top of the Lime Curd.
Sprinkle the grated chocolate over the cream and remove the key lime pie from the tin and slice.
Serve with Tesco finest* Brazilian Coffee