Salisbury Steak with Mushrooms

INGREDIENTS

• 1 pound lean ground beef
• 1/3 cup dry bread crumbs
• 1/4 cup chopped onions
• 1 egg, beaten
• 1 teaspoon salt
• 1/4 teaspoon ground black pepper
• 2 cups beef broth
• 1 large onion, thinly sliced
• 1 cup sliced mushrooms
• 3 tablespoons cornstarch
• 3 tablespoons water