…asks reader Sasha. And if not, can the cracks themselves be painted with egg wash to hide them? Both of those are good questions. Laminated pastries are prone to surface cracks because of the sheer thinness of the layers. Oven heat makes them brittle and prone to breaking and separating as the interior of the pastry expands. Keeping the exterior of the pastry moist and flexible before baking helps. I suppose that if you were determined to have a perfectly smooth top for a basic classic coffeecake, you could gently slit the “fold” side of the cake right after shaping so the expansion of the interior doesn’t exert any pull on the surface.
Concerning an egg wash “touch-up”, it is possibly to apply a little more egg wash, say about two thirds of the way through the baking process. The freshly painted surfaces will brown somewhat, though they won’t be as shiny, smooth and brown as the portions of the cake that were covered right before the bake.