Step 1

In a bowl, combine the melted butter with the granulated sugar and brown sugar. Use a wooden spoon to mix vigorously for 2 minutes.

Step 2

Stir in the egg and vanilla until smooth.

Step 3

In a separate bowl, sift together the flour, corn starch, salt and baking soda. Stir the dry ingredients into the wet ingredients, stirring just until no more flour remains. Let the dough sit at room temperature to cool for 10 minutes.

Step 4

Stir the chocolate chips into the cooled dough. The dough will be thicker now than it was before cooling.

Step 5

Divide the dough into 12 portions for medium-sized cookies and 24 portions for small cookies. Shape into balls, and flatten slightly with the palm of your hand. Refrigerate the dough balls for 25 minutes - no more, no less.

Step 6

Preheat the oven to 350 F and line a large baking sheet with parchment paper.

Step 7

Place the chilled dough 2 inches apart on the baking sheet. Bake the cookies on the center oven rack for 9 minutes (for medium cookies) or for 6 1/2 - 7 minutes (for small cookies). The cookies should still be very pale, with the edges set and the centers still underdone.

Step 8

Cool the cookies on the baking sheet for 2 minutes, then transfer to a cooling rack to cool completely.