These rolls have a delicious crackly/crunchy crust, partly the result of allowing them to proof in the refrigerator, partly from an egg white wash applied just prior to baking. Their texture is light and airy, rather than substantial, which makes them a wonderful mini-sandwich roll. Make them slightly larger, and they're perfect for hamburgers or grilled sausage. Or serve them at breakfast, with butter and preserves, as they do in Europe. Notice that this recipe includes just over 1/4 teaspoon yeast. Why so little? Because of the extra-long fermentation, key to developing the rolls' flavor. As the dough rests, the yeast will continue to multiply; thus there's no need to "front-load" with lots of yeast initially.