Preheat the oven to 350 degrees F. Mist three baking sheets with nonstick cooking spray.
Sift together the flour, baking powder, baking soda and salt. Set aside.
In a large bowl, using a hand mixer, cream the granulated sugar, brown sugar and margarine until light and fluffy, 3 minutes. Beat in the vanilla and egg until smooth and creamy. Gradually stir in the sifted ingredients. Stir in the chocolate chips. Drop by tablespoons onto the prepared baking sheets, 3 inches apart.
Bake the cookies two trays at a time, until pale golden and the edges are just set and browned but the centers are still soft, 9 to 12 minutes. Rotate the trays halfway through the baking time. Allow the cookies to cool on the baking sheets for 10 minutes. Eat warm or transfer to a wire rack to cool completely.