Cipollini Onion and Fennel Pot Roast

Name: Cipollini Onion and Fennel Pot Roast
Ingredients: 1 tablespoon chopped fresh rosemary leaves; 1 tablespoon chopped fresh thyme leaves; 1 tablespoon extra-virgin olive oil; 1 teaspoon kosher salt; 1 teaspoon freshly ground black pepper; 1 (5-pound) boneless beef chuck roast; 1/4 cup extra-virgin olive oil; 3/4 pound (about 2 cups) cipollini, boiler, or pearl onions, peeled; 3 medium carrots, peeled and chopped into 3/4-inch pieces; 2 medium fennel bulbs, sliced into 1/2-inch pieces; Kosher salt and freshly ground black pepper; 6 cloves garlic, crushed; 1 cup dry sherry; 4 cups low-sodium beef broth, plus extra, as needed; 2 dried bay leaves