The Indian flavors of this dish combine cooling spices (fennel, coriander) with the heat of a jalapeño. Remove the seeds from the pepper if you like things a little less fiery.
- ½ tsp. kosher salt plus more
- 1 2” piece ginger, peeled
- ½ medium head cauliflower, cut into small florets
- 1 tsp. yellow mustard seeds
- Cilantro leaves with tender stems (for serving)
Toss jalapeño and ½ tsp. salt in a small bowl. Finely grate ginger and squeeze juice into jalapeño mixture (you should have about 1 Tbsp. juice); discard pulp. Set jalapeño mixture aside.
Cook cauliflower in a medium pot of boiling salted water until tops of florets are slightly translucent, about 1 minute; drain and rinse under cold water. Set aside.
Cook oil and mustard seeds in a medium saucepan over medium-high heat, stirring, until seeds begin to pop, about 2 minutes. Add fennel seeds, coriander, cumin, and turmeric. Cook, stirring, until fragrant, about 1 minute. Remove saucepan from heat and mix in lime juice and reserved jalapeño mixture. Let cool; season with salt. Add reserved cauliflower to saucepan and let marinate at least 1 hour.
Top with cilantro just before serving.
DO AHEAD: Cauliflower can be made 3 days ahead. Cover and chill.