Preheat oven to 350° Fahrenheit. Line 2 cookie sheets with parchment paper. In a medium bowl, combine flour, cornstarch, baking soda, salt, and cocoa powder. Mix briefly with a fork to combine and set aside.

In a bowl of an electric mixer fitted with a paddle attachment (hand mixer and large bowl work here too), over medium/high speed, cream the butter and the sugars until light and fluffy, about 2-3 minutes. Add the eggs one at a time, beating well after each addition. Add the vanilla extract and Baileys in a stream and mix until combined. Stop and scrape the mixer to incorporate ingredients.

Turn the mixer speed to low and add the flour mixture all at once. Mix until mostly combined. It’s fine if you see some flour bits. Remove bowl from the mixer and fold in the chocolate chips. Cover the bowl with plastic wrap and place in the refrigerator for at least an hour to chill, preferably 2.

Remove bowl from fridge. With a medium sized cookie scoop, scoop out portions of cookie dough and place them at least 2" apart on the baking sheet. Place trays in the oven and baked for 9-10 minutes. The cookies should have lost their sheen and may be browned around the edges.

Remove from the oven and allow the cookies to cool on the cookie sheets for about 5, then transfer them to a wire rack to cool completely.

Makes about 45 cookies, depending on the size of your cookie scoop.

Note: If opting for 1/3 cup of Baileys, allow for a longer chilling time.