How to Make It
Soak the chiles in 1 cup of hot water until softened, about 20 minutes. Drain and finely chop to a paste-like consistency.
In a small saucepan, combine the chiles with the cream and bring to a slow simmer over moderate heat, whisking. Remove from the heat and let steep for 5 minutes.
Simmer the sauce over low heat, whisking constantly, until it is the consistency of light cream, about 3 minutes. Season with salt and cayenne; serve with lime wedges.