I’ve been making this crumb cake, or something like it, for decades—it has become my go-to when I want a buttery, not-to-sweet sort of a cake, layered with whatever fruit happens to be in season (or in the freezer). It’s perfect with rhubarb in the spring, berries in early summer, stone fruit (peaches, plums, apricots, nectarines) in late summer, and apples or pears in the fall. You can mix up the fruit, play around with citrus zest or spices in the batter or crumble, and make use of the last of the yogurt or sour cream. It’s the sort of cake you’ll get to know from memory and mix up whenever you need one, which is quite regularly for me. It’s altogether the epitome of a useful recipe.