Pastry flour is something you’ll almost never see in stores, though quite a few cookbooks call for it. Which, you know, is aggravating. The idea is that it’s not so low in protein (gluten) that it can’t stand up or rise, but not so high in protein that it will make your biscuits or pastry doughs tough. It’s made from conventional wheat and is around 8 percent protein, just a step up the ladder from cake flour, which weighs in around 6 or 7 percent. Make your own pastry flour by combining cake flour and a national brand all-purpose flour in a 50-50 ratio.