In a 12-inch frying pan or 5- to 6-quart pan over medium-high heat, stir oil, onion, ginger, and garlic until onion is limp, about 8 minutes. Add curry powder, cumin, and cayenne; stir until spices are fragrant, about 1 minute. Add 3 cups broth and bring to a boil over high heat.
Shape turkey meatball mixture into 1-inch balls and drop, as formed, into boiling broth. Cover and simmer over low heat until meatballs are no longer pink in center (cut to test), 6 to 8 minutes.
In a small bowl, mix cornstarch and 1/3 cup broth. Add to pan, stirring until sauce boils, about 2 minutes. Add salt to taste.
Mound rice on dinner plates; surround with spinach, and spoon meatballs and sauce over rice and spinach. Add chutney and yogurt to taste.
Turkey meatball mixture. In a bowl, mix 1 pound ground lean turkey, 1 large egg, 1/4 cup fine dried bread crumbs, 1 teaspoon ground coriander, 1/3 cup chopped onion, and 1 teaspoon salt until well blended.