Peanut Butter Banana Shake

1 banana 
Ice cubes 
3 tablespoons smooth peanut butter 
1 cup skim milk 
1 drop vanilla 
Peel banana and break into chunks. Add a hand full of ice cubes to blender and blend to break up. Add banana, blend. Add peanut butter, milk, vanilla and cinnamon. Blend until smooth. Pour into glass and serve.