PreparationRoast chiles: Roast chiles on their sides on racks of gas burners, 1 or 2 per burner, on medium-high (or on rack of a broiler pan about 2 inches from heat), turning with tongs, until skins are blackened all over, 4 to 8 minutes. Transfer to a large bowl, then cover and let stand 20 minutes. Peel chiles, then stem, seed, devein, and coarsely chop. Make soup: Heat spices in oil in a large heavy saucepan over medium-low heat, stirring, until fragrant and oil begins to simmer, 1 to 2 minutes. Add onion and garlic and cook, stirring, until softened, 5 to 7 minutes. Add roasted chiles and 1 1/2 teaspoons salt and cook, stirring, 1 minute. Purée chile mixture with cilantro and 3 cups broth (total) in 2 or 3 batches in a blender until smooth (use caution when blending hot liquids), about 2 minutes per batch. Return mixture to cleaned saucepan and add cream. Bring to a simmer, adding more broth to thin if necessary, and season with salt. Cooks' note:Soup can be blended and cream added (but not heated) 1 day ahead and chilled, covered. Thin with broth and season with salt when reheating if necessary.
PreparationRoast chiles: Roast chiles on their sides on racks of gas burners, 1 or 2 per burner, on medium-high (or on rack of a broiler pan about 2 inches from heat), turning with tongs, until skins are blackened all over, 4 to 8 minutes. Transfer to a large bowl, then cover and let stand 20 minutes. Peel chiles, then stem, seed, devein, and coarsely chop. Make soup: Heat spices in oil in a large heavy saucepan over medium-low heat, stirring, until fragrant and oil begins to simmer, 1 to 2 minutes. Add onion and garlic and cook, stirring, until softened, 5 to 7 minutes. Add roasted chiles and 1 1/2 teaspoons salt and cook, stirring, 1 minute. Purée chile mixture with cilantro and 3 cups broth (total) in 2 or 3 batches in a blender until smooth (use caution when blending hot liquids), about 2 minutes per batch. Return mixture to cleaned saucepan and add cream. Bring to a simmer, adding more broth to thin if necessary, and season with salt. Cooks' note:Soup can be blended and cream added (but not heated) 1 day ahead and chilled, covered. Thin with broth and season with salt when reheating if necessary.