Serve with crusty bread to dip into the flavorful broth.
Scrub mussels thoroughly with a scrub brush, removing beards. Discard any opened shells.
Sauté garlic and shallots in hot oil in a Dutch oven over medium heat 1 to 2 minutes. Stir in wine and mustard; cook 2 to 3 minutes. Add broth and salt, and bring to a boil. Add mussels. Cook, covered, stirring occasionally, 5 minutes or until all mussels have opened. Remove from heat. Stir in basil and cilantro.