1 cup masoor dal (small orange, a.k.a. "red," lentils)
3 cups water
¼ teaspoon ground turmeric
2 tablespoons vegetable oil
½ teaspoon brown mustard seeds
½ teaspoon cumin seeds
1/8 teaspoon hot red pepper flakes
½ cup well stirred canned unsweetened coconut milk
¼ cup chopped cilantro
2 teaspoons fresh lemon juice
1 teaspoon salt
Bring lentils and 3 cups water to a boil with turmeric in a 2 quart heavy saucepan, then gently simmer, partially covered, stirring occasionally, until falling apart, about 20 minutes.
When lentils are cooked, heat oil in a small heavy skillet over medium high heat until it shimmers, then cook mustard seeds, cumin seeds, and red pepper flakes until mustard seeds begin to pop and/or turn gray and cumin seeds brown, about 1 minute.
Stir spice mixture into lentils with coconut milk, cilantro, lemon juice, and salt and bring to a simmer.