Need Soft Sugar Cookie Recipe

My father has been telling us about a soft sugar cookie his grandmother used to make, unfortunately every recipe I or my Mom could come up with never was a "soft" cake-like cookie he is talking about..........

Yesterday he told me he thought she made the cookies with buttermilk.....now I've seen a couple recipes that use sour cream.....was getting ready to try one of those, but if anyone has one with buttermilk, or if you have a sure thing, please share!

Thanks! Audrey