Steamed Mussels with Fennel and Tomato

Name: Steamed Mussels with Fennel and Tomato
Ingredients: 1/4 cup extra-virgin olive oil; 5 large cloves garlic, very thinly sliced; 1 bulb fennel (with some fronds), halved and thinly sliced; 2 medium carrots, very thinly sliced; Kosher salt and freshly ground pepper; 1/4 cup dry vermouth or white wine; 1 28-ounce can San Marzano plum tomatoes, crushed lightly by hand; 2 teaspoons roughly chopped fresh tarragon; 2 pounds mussels (preferably cultivated), scrubbed well and beards pulled off; Crusty bread, for serving