In a bowl creamed together the butter and two types of sugars.
Once airy and well incorporated, add the melted butter and milk. Mix in well.
Now add the remaining ingredients (flour, coco powder, baking powder, bicarb and chocolate chips) and mix in to a cookie dough.
Split mixture into 15 balls (55g each), place in the fridge to harden. These are best if left in the fridge up to 48 hours.
Once chilled, take out of fridge 10 mins before baking.
Heat oven to 180c.
Bake for 10 minutes for a chewy cookie and longer for a crispier cookie. Anything after 10 minutes keep a eye on the cookies to ensure they don't burn.
Allow to cool before digging in!