Directions: Chop fennel bulb to measure 2 cups. Chop fennel fronds to measure 1 tablespoon. Heat a large Dutch oven over medium-high heat. Add chopped fennel bulb and garlic; sauté 3 minutes. Add 1 cup water and vermouth to pan; bring to a boil. Cover, reduce heat, and simmer for 3 minutes or until fennel is tender. Add mussels to pan; cover and cook 5 minutes or until shells open. Remove mussels from pan and keep warm; discard any unopened shells. Remove pan from heat, and add 2 tablespoons butter, stirring until butter melts. Serve fennel broth over mussels, and sprinkle with fennel fronds.