Preheat oven to 350˚F. Line 2 large baking sheets with parchment paper or silicone mats.

In a medium bowl, whisk together flour, cornstarch, baking soda, and salt until combined.

Pour butter into the bowl of an electric stand mixer fitted with a paddle attachment. Add brown sugar and granulated sugar. Beat on medium speed until well combined. Beat in egg and vanilla extract.

With the mixer on low speed, add in the dry ingredients, mixing until just combined. Stir in mini chocolate chips.

Scoop out the dough in slightly heaping 1 tsp to 2 tsp portions. Form into balls and place on lined baking sheets, spacing them about 1 inch apart. If you would like, top each with three mini chocolate chips for the look.

Bake for 6 to 8 minutes, until set. They will look soft and slightly under-baked. Remove from the oven and let them sit on the pans for about 5 minutes before removing to a wire rack to cool the rest of the way.

Store in an airtight container.