Pulverized sugar is the trick along with a smidgen of rice flour and slow baking but the real sensation here is using the crème de la crème of salts, fleurs de sel. Considered too expensive for all your cooking, fleurs de sel, harvested by skimming the top layer of sea salt, is perfect for baking. Most fine food stores have Fleurs de Sel, or try King Arthur Flour baking catalogue. By the way, if you don't have rice flour, leave it out or you can use cornstarch. These are, 'Just Sooooo" good, as one tester said - and most of our testers are praising and cursing me for sharing this recipe.