In a large bowl combine sour cream, sugar, butter, eggs and vanilla and mix until well blended.
In another bowl combine flour, baking powder, baking soda, dry banana pudding mix and salt and slowly then add to wet mixture and mix until incorporated.
With large spoon or cookie scoop crab dough (2-3 Tbs worth) and roll into a ball and place on cookie sheet, gently flatten each cookie with the palm of your hand.
Bake for about 10 minutes or until light golden.
Remove to a cooling rack and let cool.
Meanwhile make your frosting by mixing your cream cheese and butter together in bowl.
Mix in your vanilla then one cup at a time mix in your powdered sugar until you reach your desired consistency.
Frost cooled cookies and decorate with sprinkles, banana slices, etc.