Rosemary Orange Pot Roast

Name: Rosemary-Orange Pot Roast
Ingredients: 2 tablespoons chopped fresh rosemary; 3 teaspoons extra-virgin olive oil, divided; Pot Roast; 1/2 cup reduced-sodium beef broth; 1/4 teaspoon freshly ground pepper; 2 teaspoons freshly grated orange zest; 1/4 cup low-fat mayonnaise; 2 tablespoons whole-grain mustard; 3 cloves garlic, minced; 1 tablespoon cornstarch, plus more as needed; 2 large onions, halved and thinly sliced (4 cups); 1/4 teaspoon salt, plus more to taste; 1/4 cup low-fat plain yogurt; 1 tablespoon water, plus more as needed Grainy Mustard Sauce; 1 3-pound bottom round roast, rump roast or chuck roast, trimmed; 1/2 cup dry red wine; Freshly ground pepper to taste