If you like spice and heat, this is a dish for you! Enjoy the natural peppery flavor from these greens in combination with the curry. Mustard greens are packed full of phytochemicals, folic acid and vitamin K.
Rinse greens and shake off excess water. Holding a leaf in one hand by its rib, with stem pointing up, with your other hand, grasp both leafy sides and hold them together, like closing a book. Starting at stem end of leaf, pull down and tear leaf from stem and center rib, all the way to tip. Stack stemmed leaves and chop into roughly 1-inch pieces. There will be a big heap of chopped greens.
Set large, heavy skillet over medium-high heat. Add oil and swirl to coat pan. Add mustard seeds and cook, shaking pan often, until seeds look grey and start popping in 2-3 minutes. Add onion, curry powder, turmeric, pepper flakes, if using and garlic. Cook, stirring often, until onion is golden and translucent, about 4 minutes.
Add coconut and half the greens. While stirring, cook greens until coated with oil and collapsed enough to gradually add remaining greens. Continue stirring, adding 2 tablespoons water at a time to keep greens from sticking to pan. When greens are crisp-tender and onion lightly browned, serve immediately.