Combine the flour, Natvia and butter in a food processor and process until the mixture resembles bread crumbs.
Add the egg and vanilla and pulse until the dough starts to come together. Add a little iced water if the mix is too dry, or a little flour if too wet.
Roll into a ball and then flatten into a disk. Wrap in plastic and then refrigerate for 45 minutes-1 hour.
Make the lemon curd by whisking together the eggs, yolks, Natvia. Lemon juice and cream in a heat safe bowl. Place the bowl over a simmering pot of water and whisk continuously for about 10 – 15 minutes until the mixture begins to thicken.
Strain the mixture through a sieve into a bowl and then whisk through the butter until combined and smooth. Cover and refrigerate.
Roll the dough out between two pieces of baking paper. Sing a large cookie cutter cut out 1 rounds.
Grease a cupcake tray and place the pastry inside each cupcake hole. Press down along the bottom and edges
Prick holes in the bottom of each shell and then place in the freezer for 20-30 minutes.
Bake in the oven at 180C for 20-25 minutes, until golden brown.
Remove form the oven, stand 5 minutes and then place each shell on a rack to cool completely.
Fill each shell with curd and then refrigerate for3-4 hours to set.