Mussels A La Plancha
Prepare grill. Preheat a large griddle or 12-inch cast-iron skillet on a rack over very hot coals. When griddle or skillet is very hot, add mussels and cook, stirring occasionally if using skillet, until mussels are opened, about 3 minutes. Discard any unopened mussels. While mussels are cooking, in a small saucepan heat butter and salsa over moderately high heat until mixture sizzles. Remove pan from heat and stir in lime juice, salt, and epazote. Drizzle sauce over mussels.
NOTES : Plancha is simply another word for comal, or griddle.*
Available at Mexican markets and some specialty produce markets