I was going to make Ottolenghi's sweet tart cases today and noticed that the recipe calls for icing sugar (powdered) instead of regular sugar. I have never heard of this before. Any info will be greatly appreciated.
I've never made a recipe with it, but sounds fine to me. It probably incorporates well, since it's ground so fine, and the bit of cornstarch would, if having any effect, probably enhance the tenderness of the pastry.