See “No Ghee? Browned Butter Works, Too” below for instructions on making faux ghee. For less heat, remove the ribs and seeds of the serrano. Fresh curry leaves add a wonderful aroma to this dal, but if they're unavailable, you can omit them. Yellow mustard seeds can be substituted for brown. Monitor the spices and aromatics carefully during frying, reducing the heat if necessary to prevent scorching. Serve the dal with naan and basmati or another long-grain white rice.

Bring 4½ cups water, lentils, ginger, and turmeric to boil in large saucepan over medium-high heat. Reduce heat to maintain vigorous simmer. Cook, uncovered, stirring occasionally, until lentils are soft and starting to break down, 18 to 20 minutes.

Whisk lentils vigorously until coarsely pureed, about 30 seconds. Continue to cook until lentils have consistency of loose polenta or oatmeal, up to 5 minutes longer. Stir in spinach and salt and continue to cook until spinach is fully wilted, 30 to 60 seconds longer. Cover and set aside off heat. (Lentils can be refrigerated for up to 3 days. Thin with water, if desired, when reheating.)

Melt ghee in 10-inch skillet over medium-high heat. Add mustard seeds and cumin seeds and cook, stirring constantly, until seeds sizzle and pop, about 30 seconds. Add onion and cook, stirring frequently, until onion is just starting to brown, about 5 minutes. Add curry leaves (if using), garlic, arbols, and serrano and cook, stirring frequently, until onion and garlic are golden brown, 3 to 4 minutes.

Add lemon juice to lentils and stir to incorporate. (Dal should have consistency of loose polenta. If too thick, loosen with hot water, adding 1 tablespoon at at time.) Season with salt and extra lemon juice to taste. Transfer dal to serving bowl and spoon onion mixture on top. Sprinkle with cilantro and serve.

No Ghee? Browned Butter Works, Too