Step 1

In a large saucepan, combine the yellow lentils with 3 cups of the chicken stock, the ginger and turmeric and bring to a boil. Cover partially and cook over moderate heat, stirring occasionally, until the lentils are just tender, about 20 minutes.

Step 2

Transfer 1 cup of the lentils to a food processor or blender and puree until smooth. Return the puree to the saucepan, add the remaining 1 cup of stock and the zucchini and bring to a simmer. Season with salt, cover and cook over moderately low heat, stirring, until the zucchini is tender, about 15 minutes.

Step 3

Meanwhile, in a medium skillet, heat the oil until shimmering. Add the mustard seeds and cook over moderate heat, shaking the pan, until they begin to pop, about 30 seconds. Add the onion and cook, stirring occasionally, until softened, about 7 minutes. Add the garlic and serranos and cook for 1 minute. Add the cumin and curry leaves and cook until fragrant, about 1 minute. Add the tomato and cook, stirring, until softened, about 7 minutes. Stir the tomato mixture into the dal and simmer for 5 minutes. Stir in the lemon juice, season with salt and serve with Fragrant Basmati Rice.