serves 4–6; adapted from Julie Sahni, Classic Indian Cooking
Rinse lentils with water until it runs clear, then let them soak in water while you gather the other ingredients.
Heat ghee/oil in large saucepan over medium heat. Add onion and cook until softened, about 5 minutes. Add garlic, ginger, and turmeric, cook a couple minutes then add tomatoes and cook a few minutes to concentrate the flavors.
Add drained lentils, 4 cups water/coconut milk, salt, bring to boil then reduce heat to maintain a low simmer for 30 minutes, partially covered.
Heat ghee/oil over medium heat in small frying pan. Add mustard seeds and cook for a couple minutes until seeds begin to pop. Add ginger, chile flakes, cumin, and cook for a couple minutes. Stir into the finished dal or top individual servings.