How to Make It
Heat oil in a saucepan over medium-high heat. Add mustard seeds, cumin seeds, and chiles to pan; cook 1 minute. Stir in turmeric; cook 30 seconds. Add tomatoes and remaining ingredients; bring to a boil. Reduce heat, and simmer until reduced to 2 cups (about 50 minutes). Spoon into a bowl; cover and chill.