If you're using a food processor: Place bananas in a food processor and let the motor run till they've turned into soft serve. Be patient. It takes a minute or two, and the processor sounds like it's going to break, but it won't! When you have soft serve, add the blueberries, powdered ginger, 1/4 cup non-dairy milk, and lemon, and continue processing, until your mixture is creamy and scoops easily.