In a medium bowl add the butter, oil, and sugars mix until combined Add the eggs and vanilla and mix until well combined. Add the flour, baking powder, salt, and cream of tartar, mix until well blended.

Drop by teaspoonful onto ungreased cookies sheet. Bake at 350 degrees F for 10 minutes. After removing the cookies cool on cookies sheet for a few minutes before placing on cooling rack.

Decorate as desired.