Preheat oven to 350 degrees F. Grease and flour and angel food or bundt pan.
To prepare the cake: In large bowl, use an electric mixer to combine the sugar and oil until well blended. Add eggs, one at a time, beating between each addition. Break up bananas into chunks and add to batter.
Combine the flour, cinnamon, nutmeg, salt and soda; sift them together. Add slowly to the batter and continue beating. Fold in the pecans (if using).
Pour the batter into the prepared pan and bake for 1 hour. Let cool for 30 minutes before removing from pan.
To prepare the frosting: Use and electric mixer to combine the butter and cream cheese in a large bowl. Add the sugar and vanilla and continue beating until it is a desired spreading consistency.