Wash okra & pat it dry. Cut off the very tips of the pods & peel the cone shaped top. Grind the mustard seeds & put into a bowl. Add turmeric, cayenne, salt & 1/2 c water. Stir into a paste, adding a little more water if necessary. Heat oil in a large skillet over medium heat. When hot, add nigella seeds & 10 seconds later add okra. Stir fry for 10 minutes. Add spice paste & chiles. Bring to a simmer. Cover, lower heat & simmer gently for 5 to 8 minutes or until the okra is tender. Madhur Jaffrey, "A Taste of India"