You may recognize Diaspora Spice Co. by its tins, each one more colorful than the last: neon pink, glowing orange, bright turquoise. Beyond the labels are single-origin, hyper-fragrant spices: floral saffron threads from Kashmir, sticky vanilla pods from Kerala, and sharp fennel from Gujarat. The brand recently published its first cookbook. Its aim, writes founder and CEO Sana Javeri Kadri, “is to...