Preheat oven to 350 degrees. Line cookie sheets with parchment paper.

In a small bowl, stir together flour, baking soda, baking powder and salt. Set aside.

Using a mixer, beat together the butter and sugar until smooth and very fluffy. Beat in egg and vanilla extract. Gradually blend in the dry ingredients.

Roll rounded teaspoonfuls of dough into balls, and roll in sugar. Place on lined cookie sheets about 1 1/2 inches apart.

Bake 8 to 10 minutes in the preheated oven, or until lightly browned. Let stand on cookie sheet two minutes before removing to cool on wire racks.