2Place the poblano chile on a foil-lined baking sheet; broil 3 inches from the heat for 8 minutes or until blackened and charred, turning after 6 minutes. Place in a paper bag; fold to close tightly. Let stand 10 minutes. Peel, and discard the skins. Chop the chile.
3Combine the chopped chile, wine, shallots, 3 tablespoons cilantro, salt, and next 4 ingredients (through clam juice) in a Dutch oven; bring to a boil. Cover; reduce heat, and simmer for 8 minutes.
4Add the mussels; cover and cook for 3 minutes or until the shells open. Remove the mussels from the pan with a slotted spoon. Discard the unopened shells. Keep warm.
5Bring the wine mixture to a boil over high heat; cook until the mixture is reduced to 1 cup. Stir in the lime juice and butter. Pour the liquid over the mussels; toss gently. Sprinkle with the remaining 1 tablespoon cilantro. Serve immediately.