In a medium bowl, cream together the butter and sugar until light and fluffy. Beat in the egg and vanilla extract.
In a separate bowl, sift together the flour, baking soda, baking powder and salt. Gradually stir the dry ingredients into the wet mixture until all is blended.
Fold in the walnuts (if desired).
Drop rounded teaspoonfuls of dough onto an ungreased cookie sheet, about 2 inches apart.
Bake for 8 to 10 minutes in the preheated oven, or until golden brown. Allow to cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.
Interesting Facts
Austrian Tea Cakes are also known as Vanillekipferl in Austria.
The crescent shape of these cookies is meant to resemble the crescent moon.
The walnuts are traditionally left out of the recipe, but can be added for a more nutty flavor.