Preheat oven to 325. Grease a 9 inch springform pan.
Place butter, banana, sugar, vanilla, eggs and milk into a blender and process until smooth.
Mix baking soda with flour and add to blender. Process until just combined (it helps to give it a start with a spoon – give it a nice stir before you blend).
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 if you want to!) and serve!
Notes
Bananas: Use those ripe ones that are starting to get lots of brown spots – those will smoosh up the easiest.
Self Rising Flour: This is flour with a little bit of leavening in it already…you can find it in the baking aisle.
Cream Cheese: We recommend regular cream cheese (not the low fat kind) for the best texture and flavor.
Pecans: These are totally optional! But if you want to fancy up your frosting, they are a great add