Preheat oven to 350 degrees F. Line a couple of cookie sheets with parchment.
Sift or thoroughly whisk together flour, baking powder, baking soda and salt. Set aside.
Cream butter and both sugars with an electric mixer; Add egg and vanilla and beat until egg is mixed in.
Add flour mixture and stir until incorporated. Stir in chocolate chips.
Drop by rounded teaspoons onto the parchment lined cookie sheets and bake for 12-15 minutes (or longer) or until the edges start to brown.
Let cool on the baking sheet for about 3 minutes, then carefully transfer to a wire rack to finish cooling.
Notes
For mini chocolate chip cookies, preheat the oven to 300 instead of 350. Make tiny marble size rounds and bake for 18 to 20 minutes.If your cookies still don't turn out crunchy, swap out about half of the butter for shortening. Easiest way is to use 4 tablespoons of butter (2 oz) and 4 tablespoons of shortening (1.7 oz). Shortening weighs a little less because it has less water.