In a medium bowl, whisk together the flours, salt, cornstarch and baking soda. Set aside.
In another bowl, beat the butter and sugar on medium high speed until light and fluffy, about 3 minutes.
Add the egg and the vanilla and mix until well-combined.
Gradually add the flour mixture and mix on low speed until the flour is combined.
Fold in the chocolate chips.
Take 1½ tablespoons of dough and form a ball. I use measuring spoons for accuracy. Each of my dough balls weighed 1.1 ounces (32g).
Repeat with the remaining dough and place the balls on a baking sheet lined with parchment paper. Make sure there's a space of about 2-3 inches (5-8 cm) between them.
Preheat your oven to 350° / 180°C.
Place the cookie dough balls in the freezer while the oven is preheating (about 7-10 minutes).
Bake for about 11 minutes or until the edges are very light brown. Don't overbake them!
Let the cookies cool on the baking sheet for about 5 minutes.
Transfer the cookies to a wire rack to cool completely.
Store the cookies in an airtight container at room temperature for about a week.