Batons of yellow and orange carrots are pickled with an Indian-inspired spice mixture for a multihued, fiery condiment.
Heat oil in a large saucepan over medium heat. Add black mustard seeds, cumin seeds, fenugreek seeds, and urad dal. When seeds pop, add chiles and curry leaves. Cook, stirring, 30 seconds. Add onion, ginger, and garlic; cook, stirring, until golden brown, about 5 minutes.
Bring a large pot of water to a boil; add salt. Add carrots; cook until just tender, 3 to 4 minutes. Immediately plunge into an ice-water bath. Drain, and pat dry.
Toss together carrots, onion mixture, sugar, vinegar, zest, coriander, chili powder, mustard, cumin, and 1 tablespoon salt. Transfer to an airtight container. Refrigerate at least 3 days. Carrots can be refrigerated up to 1 month.