Walnut-Paste Babka with Nut Crumble

There’s a babka problem with Polish baking. The Jewish-style babkas that have surged in popularity around the world have nothing to do with what Poles call babka, or baba. In Poland, babka is a Bundt cake, while the globally better-known, twisted, filled yeast babkas are called strucle. In the last decade’s flood of babka recipes, maybe the world doesn’t need another one, but if we call it a strucla, maybe that’s the loophole to get away with just one more. Here, an impossibly light yeast d