I’m no expert, but we buy overripe bananas and freeze them, and use them with frozen berries (except when we can pick fresh blueberries and salmonberries here in the Aleutians), soy milk, and sometimes we add pineapple juice and/or coconut extract. You can use regular milk instead, or yogurt, or coconut milk. You can also throw soft tofu in for extra soy, which is very good for you. We just throw stuff in and see what we like. It’s a great way to get some of those recommended servings of fruit. And blueberries are VERY good for you – lots of antioxidants, I think.