Directions

1. In a small saucepan, combine the milk and flour. Cook over medium high heat until boiling. Remove from heat and set aside to cool.
2. When the milk mixture is cool, add the butter, shortening, sugar and vanilla. Beat with an electric mixer for 10 to 12 minutes, scraping the bottom of the bowl occasionally. Keep frosted cakes refrigerated until 1/2 hour before serving.