This refreshing drink uses nonfat plain yogurt that is frozen before it is added to the blender. The yogurt should be frozen at least 6 hours ahead.
Place yogurt in a small bowl, cover and freeze at least 6 hours or up to 2 days.
Transfer frozen yogurt to blender.
Add bananas, pineapple juice, ice cubes and brown sugar and blend until smooth.
Divide among 4 glasses.