As terrific as Breads’ challah, baguettes, Tunisian tuna sandwiches, cauliflower fritters, cheese straws, and 100-percent-rye loaves are, it’s the chocolate babka, a.k.a. krantz cake, we can’t resist. Since the bakery opened in 2013, this infernally good concoction has risen from neighborhood favorite to New York culinary icon. The twisted strands are larded with cultured butter and thickly veined with a lavish, somewhat scandalous mix of Nutella and dark-chocolate chips, which detractors call a cheat but fans recognize as the delectable innovation that it is. When it emerges from the oven, the loaf is doused in sugar syrup, which preserves its tender moistness for days.