Chocolate Chip Skillet Cookie

Preheat the oven to 325 degrees Fahrenheit. Coat a 10-inch cast iron skillet or an oven-safe skillet with cooking spray.
In an electric mixer fitted with the paddle attachment (see notes), beat the butter on medium-high speed for 1 minute or until creamy. Add the granulated sugar and brown sugar and beat for about 2 minutes or until light and fluffy. Scrape down the bowl with a rubber spatula.
On low speed, add the eggs, vanilla extract and espresso powder. Beat until well combined. Scrape down the bowl again with a rubber spatula.
Meanwhile, mix the flour, cornstarch, baking soda and salt in a medium bowl. With the mixer on low, slowly add the flour mixture to the butter/sugar mixture. Don’t over beat! With a rubber spatula or wooden spoon, stir in the chocolate chips and mix until the chocolate chips are evenly dispersed.
Using a rubber spatula or a wooden spoon, spread the cookie dough evenly into the prepared skillet.
Bake for 30 to 35 minutes or until just set in the center and lightly golden brown on the top.
Remove the skillet from the oven and let it cool slightly for about 10 minutes before serving. Top with ice cream and other toppings, if desired.