Preheat oven to 32 Grease a 9 inch springform pan.
Place butter, banana, sugar, vaniila, eggs and milk into a blender and process until smooth.
Mix baking soda with flour and add to blender. Process until just combined.
Put batter in springform pan and bake until toothpick comes out clean, about one hour.
When cake is cool, make frosting: Beat cream cheese and butter together until fluffy and well-combined. On the slowest setting, beat in sugar and then vanilla. If the frosting seems too thick to you, add a tablespoon of milk.
Frost the top only of the cake. Sprinkle with pecans and serve!