Combine the garlic and ginger with about one1 tablespoon water in a small food processor and process to a paste. Set aside.
Heat 1 teaspoon oil in a Dutch oven over medium-high heat. Add onions, tomatoes, garlic and ginger paste, cinnamon, cardamom, cloves, cumin, coriander, turmeric and salt. Cook 10 minutes, stirring occasionally.
Add the chicken and stir. Cook 15 minutes uncovered, stirring occasionally. Cover and cook 5 minutes. Add the coconut milk and water. Cover and cook 10 minutes.
Meanwhile, heat the remaining 1 1/2 teaspoons oil in a skillet over high heat until very hot. Add the mustards seeds (be careful - they'll pop out the skillet), chiles and curry leaves. The oil should be hot enough so the curry leaves crackle and turn black right away. The chiles should also turn black. Cook no more than 3 minutes. Pour this mixture into the chicken. Simmer 5 minutes longer and serve.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.