Pour ½ cup oil in a large sauce pot over medium heat. When the oil is hot, add the mustard seeds, fenugreek seeds, curry leaves, and red chiles.
Sauté for 1-2 minutes, then add the ginger and onions. Reduce the heat to medium-low and allow the onions to brown until they are dark and soft enough the smash with a spatula—about 25-30 minutes.
Add the chili powder, coriander, turmeric, and cilantro—mix together.
Raise the heat back to medium and add the tomatoes, salt, and lime juice. Simmer, stirring occasionally, until the tomatoes have disintegrated and the oil separates out—15-20 minutes.
Add ½ cup of water and 1 cup coconut milk. Bring to a boil, then turn down the heat.
In a separate skillet, heat 1 Tb. of oil over high. Add the chicken to the skillet and brown on all sides, leaving the centers pink—2-4 minutes.
Add the chicken to the curry and simmer 5-7 minutes until the chicken has cooked through. Serve over basmati rice.
Cook's Notes: I went to a small foreign market to collect some of the unique ingredients for this recipe. There, I had no trouble finding everything on my list. Extra curry leaves can be wrapped and frozen for later use. This is a GREAT make-ahead! Letting the curry sit overnight enhances the flavors!