Cream together the shortening, sugar, molasses and honey in a bowl with an electric mixer. Add the egg yolks and mix well.
Sift together flour, baking soda, baking powder, salt and spices; stir into the shortening mixture. Wrap the dough in plastic and chill well until firm (1 to 2 hours).
Preheat oven to 350 degrees F.
Roll out dough on a lightly floured surface to ¼ inch thickness. Cut out shapes with cookie cutters and transfer to lightly greased cookie sheets.
Bake cookies for 8 to 10 minutes. Let cookies cool on baking sheets until they are firm. Then transfer to a rack to cool completely.
ICING
Beat powdered sugar, butter, milk and vanilla until smooth, adding more sugar or milk as needed. If desired, divide icing among smaller bowls and tint with different food colorings.