Mix shortening, sugar, egg and vanilla thoroughly.
Blend the dry ingredients; add to the sugar mixture alternately with sour cream.
Divide dough; roll out to 1/4″ thick on well-floured counter. Cut with 2″ cutter; place on a parchment lined baking sheet. If not icing the cookies, you can at this point sprinkle them with sugar.
Bake 8 to 10 minutes, or until lightly browned. Let cool.
To make glaze: Mix the powdered sugar and milk and whisk well. Add food coloring if using. Glaze the cookies and set aside to let the icing set up.