1 1/2 pounds skinless, boneless chicken breast halves
1 large (16 ounce) package frozen sliced mushrooms
2 onions, halved
1 cup butter or margarine
1 egg
1 cup white sugar
1/2 teaspoon salt
3 tablespoons all-purpose flour
4 tablespoons white sugar
1/2 cup milk
Place chicken, mushrooms and onions in a shallow dish or bowl. Pour butter in a saucepan and bring to a boil; boil for only 3 minutes. Remove from heat and stir in sugar, salt, flour, sugar and milk.
Pour broth mixture into a large, shallow dish or bowl and stir in chicken and onion. Cover, and refrigerate for at least 4 hours so the liquid can simmer.
Remove chicken from marinade, discard marinade and let cool completely. Place chicken in a large glass dish.
Cool slightly before cooking. Arrange mushrooms on bottom of chicken breast halves and sprinkle with onions and mushrooms. Divide mushroom mixture between 2 chicken halves. Spoon mushroom mixture over chicken, then top the chicken with mushrooms. Roll up and secure with aluminum foil.
Cut chicken into 1 inch pieces and arrange on foil.