Bake pie shells in pre-heated 325-degree oven, 6 minutes. Let cool. In blender, combine next four ingredients, 2 tsp vanilla and ½ cup yogurt. Add cheese. Blend till smooth. Pour equal amounts into crusts and bake on a cookie sheet at 325 degrees for 50-60 minutes or until almost set.

Combine ½ cup yogurt, powdered sugar and 1 tsp vanilla. Mix till smooth. Pour over hot cheesecake. Cool on wire rack.