In a bowl, mix together flour, baking powder, baking soda, salt then set aside.
Cream the butter, brown sugar, granulated sugar and vanilla. Add eggs one at a time, beating well. Gradually add the dry ingredients. Beat until the ingredients are thoroughly mixed. Stir in the white chocolate morsels.
Drop batter by teaspoonfuls onto the baking sheets; bake 8-10 minutes, 350°
Transfer the cookies to a wire rack to cool.