Combine the dry ingredients in a food processor, then add butter and pulse until mixture resembles breadcrumbs. Add egg yolks and process until mixture forms a dough. Flatten dough into a disk, wrap in plastic wrap and refrigerate 1 hour.
Roll dough out on a floured surface to 5mm thick. Place in a floured 22cm tart tin with a removable base, trim edges and refrigerate 15 minutes. Line with baking paper, fill with rice or dry beans and bake at 180 degrees C for 20 minutes. Remove paper and rice or beans, brush pastry with beaten egg and bake for a further 5 minutes or until golden brown. Remove and turn oven down to 150 degrees C.
To make the tart:
Blend juice and caster sugar in a blender until combined. Add eggs and process until sugar dissolves. Mix in 300ml cream. Pour filling into tart shell and bake 15 minutes or until filling is just set. Cool and dust with icing sugar.