How to Make It
Preheat the oven to 350°. In a small bowl, whisk the all-purpose flour with the oat flour, baking powder, baking soda and salt.
In the bowl of a standing electric mixer, beat the butter with the brown sugar and granulated sugar until small crumbs form, about 2 minutes. Beat in the egg and vanilla. At low speed, gradually beat in the flour mixture and the chopped chocolate.
Using a 1 3/4-inch scoop (#40) or a heaping tablespoon, arrange scoops of dough 2 inches apart on the prepared baking sheets.
Bake the cookies for 12 to 14 minutes, until golden at the edges. Let the cookies cool for about 2 minutes, then transfer to a wire rack to cool.