Of all the flours, pastry flour has the lowest protein content, hovering around 8%. (For reference, all-purpose flour has about 10-12% protein.) By using a lower-protein flour, there is less gluten development, which results in supremely tender baked goods.  That said, yeasted doughs (like for these cinnamon rolls without eggs) rely on gluten structure to poof up and become fluffy. I personally haven’t tried making this recipe using pastry flour, so I wouldn’t recommend it. If you try it, though, let me know how it turns out in the comments below!