Preheat the Oven:
Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper or a silicone baking mat.
Cream the Butter and Cream Cheese:
In a large mixing bowl, use a hand or stand mixer to beat the softened butter and cream cheese until smooth and creamy.
Add the Sugars:
Add the brown sugar and granulated sugar to the butter mixture. Beat until light and fluffy.
Incorporate Wet Ingredients:
Mix in the egg and vanilla extract until well combined.
Combine Dry Ingredients:
In a separate bowl, whisk together the flour, cornstarch, baking soda, and salt.
Form the Dough:
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Stir in the chocolate chips by hand to ensure even distribution.
Portion the Dough:
Scoop the dough into tablespoon-sized balls and place them on the prepared baking sheet, spacing them about 2 inches apart.
Bake the Cookies:
Bake for 9–11 minutes, or until the edges are set and the centers look slightly underbaked. The cookies will firm up as they cool.
Cool and Serve:
Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.