Lime-Tart Pigeon Pea Broth with Coconut

Usually tamarind-based broths, rasams are an everyday feature of Tamil home kitchens. Sometimes tart fruits like lime juice, pineapple, and unripe mango fill in for the tamarind to provide a change of pace. I love the clean sharpness of lime juice, a polar opposite of the earthy, complex, murky tamarind. I always add it after the broth is fully cooked and seasoned, because if lime juice is exposed to heat for too long, it can turn bitter. Ladle this rasam over cooked white ric