"Arroz Con Camarones" Rice with Shrimp
Wash the shrimp and blot dry. Place the fish stock and shrimp shells in a saucepan and gently simmer, covered, for 10 minutes.
Roast the tomatoes, onion, chiles, and garlic in a comal or frying pan over medium heat until nicely browned on all sides: 8 to 10 minutes for the tomatoes and onions, 4 to 6 minutes for the chiles and garlic; or roast under the broiler or on a barbecue grill. Transfer to a plate to cool.
Seed the chiles. (For a spicier rice dish, leave the seeds in the chiles.) Place the roasted vegetables in a blender with two-thirds of the cilantro and the salt and pepper, and purée to a smooth paste.
Heat the oil in a large, nonstick frying pan or deep sauté pan. Add the rice and cumin and fry over medium-high heat until the rice grains are shiny, about 2 minutes. Add the tomato mixture and bring to a rolling boil. Strain in the fish stock and bring to a boil. Stir in the shrimp and bring to a boil. Reduce the heat to its lowest setting and cover the pan. Cook until the rice is tender and the shrimp is done, 18 to 20 minutes. Remove the pan from the heat and uncover. Drape a dishcloth over the pot and the rice again. Let stand for 2 minutes. Add the remaining cilantro and salt and pepper to taste, stirring them into the rice and fluffing it with a fork. Serve at once.