I got this recipe from Ellie Krieger's The Food You Crave. There is something about this smoothie that really hits the spot, and I like that it does not call for ice. Take an overripe banana, peel it, cut it into pieces then freeze it in a ziplock bag. I like to use Stoneyfield Farm Organic French Vanilla nonfat yogurt (Ellie's recipe calls for plain, if you'd prefer). The banana and the yogurt flavors tend to overpower the peanut butter, but it's very creamy and delicious. I keep my natural peanut butter in the fridge to keep the oil from separating.