In a large bowl, cream together shortening and sugar.
Add egg and vanilla, mix well.
Add sour cream, mix well.
Add dry ingredients and mix until just combined. The dough shouldn't be sticky to touch.
To avoid marring the chocolate dough with white flour, lay down a large piece of parchment. Flatten the dough slightly with your hands and then lay another large piece of parchment over top.
Roll it out about 1/4 inch thick and cut into desired shapes.
Place cookies on a greased or lined sheet pan and bake at 350 degrees F for about 10 minutes.
When the cookies are done, they should be dry on the top and the bottom.
For the Icing
Mix powdered sugar and vanilla.
Add milk 1 tablespoon at a time until icing reaches desired thickness.
Stir in orange zest, if using.
Divide and color icing as desired.
The sour cream can be substituted for plain greek yogurt. The number of cookies you get from this recipe will vary depending on how thick you cut them and how large or small your cookie cutters are.If you would like to make the cookies thinner or thicker, remember to adjust the baking time accordingly.Try and use cookie cutters that are all the same size, that way the cookies will bake evenly.