Whisked together flour, cocoa powder, baking soda, and salt. Once combined set aside.
Using a stand mixer or electric mixer beat softened butter with melted chocolate, sugar, and brown sugar. Once well combined add in egg, vanilla extract, and milk. Add in dry ingredients and mix until well combined.
Place dough in the fridge and allow to chill for at least 2 hours.
Pre heat oven to 350 degrees F. Prepare a baking sheet with parchment paper
Place sprinkles on a plate. Scoop out 1 1/2 tbsp of dough and place in the sprinkles. Roll the dough until completely covered in sprinkles. Place sprinkle covered cookie onto your prepared baking sheet.
Bake for 12-13 minutes.