1 tablespoon Worcestershire sauce
4 tablespoons brown sugar
1 1/2 cups beef broth
2 tablespoons white sugar
1 teaspoon dry mustard
3/4 teaspoon salt
1 1/2 onion, diced
1 cup milk
6 (5 ounce) cans cornstarch
In a medium bowl, mix Worcestershire sauce, brown sugar, beef broth, white sugar, mustard and salt. Pour mixture over cornstarch in slow cooker, stirring to coat. Cover and cook on low for 6 hours.