I have made this frosting before and it was the best frosting I have ever had. My recipe was slightly different, instead of shortening, I used one cup butter, and one cup sugar. Tonight I tried making it again, and it curdled. I'm not quite sure why. I softened my butter to room temp, and beat the sugar and butter for almost 20 min, and it was still slightly grainy. I used skim milk. Could that be it? Or did I beat it too long? Any input would be great. I absolutely love this recipe! Thanks. Oh, and I completely cooled the flour and milk so I don't think temperature was the issue.

Reviewed On: Dec. 27, 2011