For the Cake:
Sift flour, baking powder, baking soda, spices and salt together.
Cream shortening with sugar and vanilla until creamy.
Add eggs one at a time and beat thoroughly after each addition.
Combine bananas and milk.
Add dry ingredients and banana mixture alternately in small amounts to and beat thoroughly after each addition.
Pour into 2 greased 8" pans and bake at 375° oven for 25 to 30 minutes.
Turn onto racks and let cool completely then frost.
For the Caramel Frosting:
Combine sugar and sour cream in a pot and cook until temperature of 238°.
Add butter and vanilla and cool to lukewarm. Beat in powdered sugar until spreading consistency.