In the summer I want mine to be cold and thick like a milkshake so I freeze 1/2 cup of Carnation Evaporated Milk; it comes nonfat, low fat, and regular. I use Glad 1/2 cup reusable plastic snap lid bowls. 1 can fills 3 of the 1/2 cup things.
I also freeze the bananas; peel them, break them into 2 pieces or more, wrap in plastic wrap and put in a plastic bag and into the freezer.
I use frozen fruit from the grocery store freezer section; about 50 grams.
50 grams of any frozen juice concentrate, undiluted; my favorite is Dole Mango, Peach, and Orange. http://www.dole.com/Products/Juice
Liquid can be yogurt, buttermilk or Almond Breeze. Buttermilk gives it a kick from its salt.
The Carnation evaporated milk is the magic ingredient; it makes it nice and rich.