Thai-Style Grapefruit and Prawn

Fill a large pot with lightly salted water and bring to a rolling boil over high heat. Once the water is boiling, stir in the shrimp, and return to a boil. Cook the shrimp until they are bright pink on the outside and the meat is no longer transparent in the center, 3 to 5 minutes. Drain and set aside to cool. Combine the grapefruit, onion, avocado, lime juice, fish sauce, chile pepper, and brown sugar in a large bowl. Top grapefruit salad with cooked shrimp, and sprinkle with chopped cilantro.