In a stand mixer, cream the shortening, then gradually add the sugar and continue creaming until it is light and fluffy. Blend in the eggs.
In a separate bowl, sift together the flour, baking powder, soda, salt and spices. Set aside.
In a small bowl, whisk together the pumpkin and milk.
Add the dry ingredients alternately with the pumpkin mixture to the egg mixture, beginning and ending with dry ingredients.
Grease and flour two 9" round cake pans. Pour the batter into the prepared pans, dividing equally.
Bake the cakes in a 350 degree oven for 20-22 minutes or until the top center of the cake bounces back when you touch it.
While the cake is baking, prepare the cream cheese frosting.
Using an electric mixer, mix the butter and cream cheese, scraping down the sides as needed, until the mixture is light and fluffy. This will take about 2 minutes. With the mixer on low speed, add the powdered sugar, 1/2 a cup at a time, until it is thoroughly mixed. Add the vanilla and beat the frosting on medium speed for about 3 minutes.
Place one cake down on a cake plate. Frost the top of this cake with a thick layer of frosting.
Then place the second cake on top of the frosted layer.
Frost the top and sides of the cake, getting the frosting as even as possible.
If desired, press the chopped pecans around the outside of the cake immediately after frosting.
Store the cake in the refrigerator.
*In place of the pumpkin pie spice, you could use 1/2 teaspoon each of ginger and nutmeg.