The Hirshon Oaxacan Stone Soup - Caldo De Piedra

Name: The Hirshon Oaxacan Stone Soup - Caldo De Piedra
Cuisine: American, Mexican, Latin American
Ingredients: 8 ounces large freshwater prawns, diced and blanched in hot water; 4 tsp. minced serrano chile; 4 tsp. minced yellow onion; 2 tsp. chopped fresh cilantro; 2 tsp. fresh epazote leaves, chopped; Finely-julienned tortilla strips, fried crisp (optional but recommended); 4 screaming-hot river stones; Stone Soup Fumet, as desired (recipe follows; see Note); 4 lime wedges; ***; ⅔ cup roughly-chopped garlic; 2 serrano chiles, split in ½ lengthwise; 1 bunch cilantro, chopped; ½ cup finely-chopped yellow onion; 2 lbs. shrimp or lobster carcasses; 1 (28-ounce) can whole tomatoes, puréed; 1 gallon bottled water; Kosher salt, to taste