This breakfast casserole riffs on the chocolate-cinnamon flavors in babka to create a sweet and filling dish that can feed a crowd. Slices of bread (challah or Pullman loaves work great here) spread with Nutella and a sweet custard infused with a whiff of cinnamon bake to create a pure delight, sitting somewhere between French toast, babka, and bread pudding. Shingle the bread in a wave-like pattern to create a striking visual reminiscent of the spirals found in a classic braided babka. Brushing the hot babka bake with simple syrup, then baking it for an extra 10 minutes caramelizes the sugar, providing a crisp contrast to the custardy interior.
The best part: You can completely assemble everything in the baking dish, wrap it in plastic wrap, and stash it in the refrigerator overnight, so all you have to do is pop it in the oven in the morning.