To make the crust, mix together the butter and sugar until creamy and well blended. Mix in the vanilla extract and egg until well blended. Mix in the flour, baking powder, salt, pecans, and grapefruit zest until well blended and a thick and pliable dough much like a cookie dough, is formed. Pat the dough evenly into the bottom of the pan.
Ruby red grapefruit chess bars | www.homesicktexan.com