"Thanks to the sour cream my recipe for Apple Streusel Coffee Cake is wonderfully moist and keeps well. But even better the streusel adds crunch so it's texturally interesting. I developed the recipe for a class on brunch dishes I taught at Williams-Sonoma a few years back and it's been part of my repertoire ever since because it can be made the day before and if cooled and stored in a plastic cake tastes completely fresh the next day. (Larger image.)..."