1. Preheat oven to 350 degree F, and make sure the oven rack is in the center position.
2. Sift flour, baking powder, baking soda, and salt into a medium bowl, and set aside.
3. Place butter, sugar, and light brown sugar in the bowl of an electric mixer; cream the ingredients on high speed. Scrape down the sides of the bowl with a rubber spatula.
4. Add vanilla extract and egg; combine on medium speed. Add flour mixture and combine on low speed -- just until the batter is stiff. Turn off mixer and fold in chips with a spoon.
5. For each cookie, scoop 2 Tbs. of dough, about 2 inches apart, onto nonstick baking sheets. Using the back of a spoon, press down on each ball to slightly flatten.
6. Bake cookies until golden brown, about 20 minutes. Remove from oven; using a metal spatula, transfer to wire racks to cool.