In the blender (I used my bullet) add the yogurt, sweetener, peel of one lemon, lemon juice and ice. Blend for at least 2 minutes until an icee consistency forms. Stopping and adding another cube or two may help.
1 lemon, 3 packets sweetener, ½ cup non-fat plain yogurt, about 8-10 ice cubes.
I poured mine in a coffee mug, topped with some of the saved peel and ate with a spoon. It was exactly what I needed tonight.