Combine dry ingredients. Add oil, buttermilk, and molasses. Mix at medium speed 2 minutes. Add eggs and vanilla then beat 2 more minutes. Pour into prepared pans and bake 25 to 35 minutes. Allow to cool 15 minutes before removing from pans to finish cooling on rack.
Beat together cream cheese and butter. Add peanut butter and vanilla. Gradually add sugar. Beat to spreading consistency. Frost each layer as cake is assembled. Garnish as desired.