Streuselkuchen (German Crumb Cake) vs Pudin de Pan (Spanish Bread Pudding)

Both desserts lean on milk, butter, egg and lemon, yet they put them to very different work. In the Streuselkuchen, milk, egg and a little softened butter enrich a soft yeast dough, while cold butter rubbed with flour and sugar forms a thick layer of distinct crumbs on top; lemon zest is only an optional accent in the dough. The Pudin de Pan instead warms milk with lemon peel and cinnamon, soaks stale bread into a lumpy paste and binds it with eggs and vanilla, baking into a set, springy pudding, optionally dotted with raisins.