Cranberry Balsamic Roast Beef

Ingredients

• 3 to 4 lbs beef roast (chuck roast is preferred)
• Salt
• freshly ground black pepper
• 2 tablespoons olive oil
• 1 cup beef broth
• 1 cup fresh or frozen cranberries
• 1 cup balsamic vinegar
• 1/2 cup brown sugar
• 2 tablespoons Dijon mustard
• 4 cloves garlic, minced
• 2 teaspoons dried thyme
• 1 teaspoon dried rosemary
• 1 large onion, sliced
• 2 tablespoons cornstarch
• 2 tablespoons water