Preheat oven to 350 degrees F.
In a bowl, whisk together the flour, the baking soda, the spices, and a pinch of salt.
In another bowl, with an electric mixer cream together the shortening and the granulated sugar, beat in the egg, and beat in the flour mixture alternately with the molasses mixture, beating well after each addition.
Divide the batter among 12 paper-lined 1/2-cup muffin tins and bake the cupcakes in the middle of an oven for 15 to 20 minutes, or until a tester comes out clean. Turn the cupcakes out onto a rack and let them cool completely.
In another bowl, beat together the cream cheese, the butter, and the confectioners' sugar until the icing is fluffy and spread the icing on the cupcakes.