Yogurt Cookies?

My Grandma used to makes wonderful yogurt cookies. They were like a sugar cookie, only made with plain yogurt and soft and so flavorful. They melted in your mouth - I can still taste them, fifteen years later. She'd sprinkle a little sugar on the tops of them, too. When she died, Grandpa threw away a lot of things, including her recipe for them. :o( Does anyone have a recipe for these? *sniffle* I need my fix!!