Freeze the fruit. One key to the thick, creamy texture of this smoothie is definitely the frozen banana and blueberries! It’s a great way to use up overripe bananas, too. When you have dark bananas on your counter, just peel them, slice them, and wrap them individually. Stick the sliced bananas into the freezer and pull them out as you need them. Similarly, you can freeze fresh blueberries in ½-cup portions, or you can purchase a bag of frozen blueberries at the store.