Preparation Wash dal in several changes of water until water runs clear and drain well in a sieve. Cook dal at a bare simmer in 1 1/2 cups water in a 3-quart saucepan until most of water is evaporated and dal has consistency of a paste, 40 to 45 minutes, stirring frequently during last 15 minutes to prevent scorching. Heat ghee in a 6-quart heavy saucepan over moderately high heat until hot but not smoking, then cook mustard seeds and red chile, stirring, until seeds begin to pop. Add 1 1/2 cups water and remaining ingredients (but not dal paste). Bring to a boil and simmer, stirring occasionally, until tomatoes are softened, 6 to 8 minutes. Add dal paste and remaining cup water, stirring to incorporate. Bring rasam to a boil, stirring occasionally, and season with salt. Cooks' note:· Rasam may be made 2 days ahead and chilled, covered. Add water to thin, if necessary, before reheating.
Preparation Wash dal in several changes of water until water runs clear and drain well in a sieve. Cook dal at a bare simmer in 1 1/2 cups water in a 3-quart saucepan until most of water is evaporated and dal has consistency of a paste, 40 to 45 minutes, stirring frequently during last 15 minutes to prevent scorching. Heat ghee in a 6-quart heavy saucepan over moderately high heat until hot but not smoking, then cook mustard seeds and red chile, stirring, until seeds begin to pop. Add 1 1/2 cups water and remaining ingredients (but not dal paste). Bring to a boil and simmer, stirring occasionally, until tomatoes are softened, 6 to 8 minutes. Add dal paste and remaining cup water, stirring to incorporate. Bring rasam to a boil, stirring occasionally, and season with salt. Cooks' note:· Rasam may be made 2 days ahead and chilled, covered. Add water to thin, if necessary, before reheating.