1) Sieve the flour into a large bowl with the zest, sugar and salt. Mix well.
2) Add the butter and rub in to a breadcrumb mixture.
3) Pour in a few tablespoons of cold water and start to bring the mixture together. Add a tablespoon of water at a time as needed to work into a dough. Wrap and chill for 30 minutes.
4) Beat together the yogurt, lemon juice and zest, honey, cornflour and vanilla essence.
5) Roll the pastry out to line your pie tin. Cover with foil and baking beads, and blind bake for 10 minutes at 180 degrees C. Allow to cool, removing the foil and beads.
6) Pour the yogurt filling into the cooled pastry base, then return to the oven for 40-45 minutes until set.
To test if it's done, gently shake the tin - it should just wobble ever so