This is a traditional Short Crust Pastry made without sugar, the way it was originally made. In today's age of high sugar intake, it's a good idea to cut back when you can and as a lot of tarts and flans have sweet or savoury filling, there really is no reason to make the base sugary, in fact it tastes so much better this way.
I just wanted to say thank you for your site. I discovered it via Anna Olson, my baking mentor. Finding high quality cooking videos that really teach you about food and techniques is such a challenge and yours are amazing. I can't wait to do some recipe testing and love that it is so easy to email yourself the recipes!