Baileys Double Chocolate Cookies:
Preheat the oven to 350 degrees and line a large baking sheet with parchment paper. Set aside.
In a large bowl with hand mixer (or with a standing mixer), cream butter, granulated sugar, and brown sugar together until light and fluffy.
Add in the egg and egg yolk, and mix until combined.
Next, add in vanilla extract, Baileys Irish Cream, and melted chocolate. Mix until well combined.
Add in the flour, cornstarch, cocoa powder, salt, baking powder, and baking soda. Mix until well combined.
Lastly, add in the chocolate chips and mix until combined.
Roll cookie dough into about 1 - 1 1/2 Tbsp balls (you can use a cookie scoop or your hands) and place them evenly apart on the cookie sheet.
Gently flatten the tops of the chocolate cookie dough. This ensures they bake with a flat surface, which makes frosting the cookies easier.
Bake for 9-10 minutes, or until the edges just look set (they will continue to bake as they cool on the pan so we don’t want to over bake them).
Allow to cool on the baking sheet for 5-10 minutes, then transfer to a wire rack to finish cooling.
Cream Cheese Frosting:
With a standing mixer or an electric hand mixer, cream butter and cream cheese together until well combined.
Add in powdered sugar and a pinch of salt (salt helps cut through the sweetness of the frosting) and mix until well combined.
Lastly add in Baileys and vanilla extract and mix until combined.
Using a piping bag or an offset spatula (a knife or back of spoon works as well), frost each cookie. Top with chocolate shavings or cocoa powder, if desired.
Refrigerate leftovers.