Preheat the oven to 375 degrees F (190 degrees C).
Sift together the flour, baking powder, baking soda, and salt; set aside.
In a medium bowl, cream together the butter, brown sugar, and white sugar until smooth. Beat in the egg and vanilla. Gradually stir in the sifted ingredients, then stir in the chocolate chips. Drop by rounded tablespoonfuls onto ungreased cookie sheets.
Bake for 8 to 10 minutes in preheated oven. Allow cookies to cool on baking sheet for 5 minutes before transferring to a wire rack to cool completely.