Jewish-style babkas originated as a way to utilize leftover challah dough. To keep the pastry kosher, no dairy was allowed, so both the dough and filling typically were oil-based. These days, bakeries across the globe have reinvented the classic, crafting buttery babkas with creative fillings and toppings. We set out to make a babka in this style: rich, plush and complete with two flavor variations. The first features dark chocolate and nutty tahini, which complement each other beautifully. For the second, we combine cinnamon, brown sugar and walnuts with a hint of orange. Both babkas are brushed with flavored syrup, which gives them a shiny, sweet crust and locks moisture in the loaves, keeping them fresh for up to three days. Once fully cooled, you also can wrap the babka tightly in plastic wrap, then enclose it in foil and freeze for up to a month. To refresh, thaw the still-wrapped loaf at room temperature (this takes about 30 minutes), then completely unwrap, place on a baking sheet and warm in a 300°F oven for about 15 minutes.