Step #1 Sift flour, baking soda, cream of tartar & salt together.
Step #2 Beat butter, oil, sugar & confectioner's sugar in separate mixing bowl until creamy.
Step #3 Add eggs & vanilla & beat until smooth.
Step #4 Add dry ingredients slowly & beat until well mixed.
Step #5 Chill, covered for 1 hr.
Step #6 Shape dough into 1 inch balls & coat balls with extra sugar.
Step #7 Arrange balls on ungreased cookie sheet.
Step #8 Flatten with bottom of glass dipped in sugar.
Step #9 Press in extra color sugar for holiday decoration.
Step #10 Bake at 350 degrees for 8-10 mins or until lightly brown.
Step #11 Cool & store this in airtight container.
Step #12 For variations: Add 1 tsp of almond extract or lemon extract, add 1 TBS crushed peppermint candies, roll in colored sugar for holidays, add 1 TBS finely sliced lemon zest, add 1/2 crushed almonds or hazelnuts, or use decorative glass to create pattern on each cookie.