Blend all the ingredients in a small blender or use the small cup for your bullet. Pulse for a but and then work everything back towards the blades. There is just enough liquid to get it moving.
1 ½ frozen banana, 75 g pasteurized egg whites from the carton, 1 tablespoon powdered peanut butter
Enjoy immediately.
Notes
This recipe is just enough liquid to get things moving. I generally work the ingredients towards the blades manually while it's blending in my bullet as I do in this older video.
I'm going for PB flavor here. You can, of course, skip the PB powder and add other fruits or flavoring. Banana Soft Serve is really versatile.
You may think I'm crazy with the egg whites, but they are pretty much 90% water and about 10% protein. They also help add more of a creamy texture. If the thought of egg whites creeps you out (it shouldn't, but that's another story), you could use milk, almond milk or even water.