Line a baking sheet with parchment paper and set it aside.

In a medium-sized bowl, whisk the flour, cocoa powder, baking soda, and salt together. Set this bowl aside.

In the bowl of a stand mixer, cream the butter and sugars together for a few minutes until they are light and fluffy. Beat in the egg and add the vanilla extract and Irish cream.

Little by little, add the dry ingredients to the wet, on low speed. Scrape down the sides of the bowl as necessary. Add the mini chocolate chips and turn the speed up a bit higher to incorporate them throughout the thick dough.

Next, you’re going to want to scoop and chill the cookie dough. Unfortunately, the chilling is necessary. But trust me, it's worth it!

Scoop and roll the cookie dough into 1.5 tbs-sized balls. Place them on the prepared cookie sheet. Cover the dough with plastic wrap and chill for at least 3 hours, and up to overnight. When slightly impatient, I've been known to put my cookie dough that requires chilling into the freezer (for 1-2 hours) instead of the fridge. I haven't run into any issues yet!

When you’re ready to bake, preheat the oven to 350 degrees F and line another baking sheet with parchment paper. Move half of the dough balls over to the other cookie sheet, leaving a couple of inches between each dough ball.

Bake the cookies for 9-10 minutes. Allow the cookies to cool on the cookie sheets for 5 minutes or so before removing them to a wire rack to finish cooling completely.