01 -
Combine softened butter, cream cheese, light brown sugar, granulated sugar, egg, and vanilla extract in the bowl of a stand mixer fitted with the paddle attachment. Beat on medium-high speed until well-creamed, light, and fluffy, approximately 5 minutes.
02 -
Stop mixing, scrape down the sides of the bowl, and add the all-purpose flour, cornstarch, baking soda, and optional salt. Mix until just combined, about 1 minute.
03 -
Add the chocolate chips and chunks. Beat briefly to incorporate, or fold in by hand.
04 -
Using a 2-inch cookie scoop, form 28 heaping mounds. Place them on a large plate, flatten slightly with your palm, cover with plastic wrap, and refrigerate for at least 2 hours or up to 5 days. Do not bake unchilled dough.
05 -
Preheat the oven to 175°C (350°F). Line a baking sheet with a Silpat non-stick baking mat or spray with cooking spray. Place the chilled dough mounds on the baking sheet, spacing them at least 2 inches apart.
06 -
Bake the cookies for 8-9 minutes or until the edges are set and the tops are beginning to set. Do not bake for longer than 10 minutes; they will set as they cool.
07 -
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a cooling rack. Store in an airtight container at room temperature for up to 1 week, or freeze for up to 3 months.