Request for chocolate sauce recipe

[NancyRogers]

I recieved a jar of chocolate sauce from a customer last year for Christmas- was delicious. She gave me the recipe for it but have moved and misplaced the recipe. Have searched the Bordens site and it is not there. Please help as I want to give it this year.
Darlene

[Linda]

1 can Bordens sweetened condensed milk
1 (1 lb.) can Hershey's syrup
1 c. powdered sugar
1 tsp. vanilla

Mix milk, syrup and powdered sugar in top of double boiler. Cook until thick (about 1 hour). Add vanilla. Serve on ice cream.