Preheat oven to 350 degrees.
Cream margarine & vegan sugar, add vanilla, mix well. Add flour, baking soda & cream of tartar, mix well. Fold in the Rice Krispies. Place heaping teaspoon on ungreased cookie sheet and bake 10 to 12 min. Wait a minute or so before removing from baking sheet. Sprinkle with powdered vegan sugar while warm (optional). Enjoy. You can make half the recipe as this makes a large batch.