In a bowl, combine the flour, cocoa powder, and baking powder. Set aside.
Whisk butter, sugar, brown sugar, and egg until combined.
Add in Baileys and flour mixture; then fold using a spatula or wooden spoon until the dough comes together. Refrigerate for 30 minutes.
Take a scoop of cookie dough and flatten it out into a small dish. Take a spoonful of chilled Nutella and place it in the center. Pinch the seams like a dumpling. Roll into a ball and place on a baking sheet.
Bake in the oven at 350F for 10 minutes, then let cool for 5 minutes before serving.