Line 2 9x13 baking sheets with parchment paper and grease with butter or non-stick spray. Sift dry ingredients into a small bowl, and mix in chocolate chips.
In a larger bowl, cream together the butter with the sugars until light.
Whisk in the egg and vanilla extract until fluffy.
Fold in the dry ingredients until combined.
Divide into 12 balls, and place on the baking sheets.
Wrap in plastic wrap, and refrigerate for 30 minutes while your oven preheats to 350°F.
Bake for 12-15 minutes until golden brown.
Cool on baking sheet for 3 minutes before transferring to a wire rack to cool completely.