Wholesome Brisket with Roasted Vegetables

Name: Wholesome Brisket with Roasted Vegetables
Ingredients: 4 3/4- to 5-pound brisket, trimmed but not completely fat free; 1 head garlic, top 1/4-inch sliced off; 4 teaspoons olive oil; 3 small onions (about 12 ounces total), peeled, root end kept intact, cut in half lengthwise, each half cut into 3 wedges; 1 pound carrots, trimmed, peeled, and cut into 3- to 4-inch pieces; 1/2 cup water; 2 cups drained and mushed whole plum tomatoes, plus 1/4 cup reserved roasting liquid or one 16-ounce can whole tomatoes with liquid; 1 small bay leaf; Kosher salt, to taste; Freshly ground black pepper, to taste