You will have better results if you freeze the banana and use frozen pineapple. Fresh is always great too.
**tip- I've found the best way to freeze banana is in foil wrap, cut it into pieces first.
Just add everything to the blender but save some cookie for garnish.
It's ready to blend. At this point blend until it's smooth. Because it is like banana pudding you may want leave some chunks or put the cookie in last. It's your preference.
A delicious healthy treat. You may add a simple syrup if you like it sweeter. If it's an adult crowd you may want to add rum. Enjoy!