Preheat the oven to 180C/160C Fan/375F and line 2-4 baking trays with parchment paper.
Cream together butter and both sugars until light and fluffy, using an electric mixer for ease.
Add vanilla and egg, mixing until well combined.
Stir in cocoa powder, flour, bicarbonate of soda, baking powder, and salt to form a thick dough.
Fold in chocolate chips and spoon dough onto trays, leaving space between each cookie.
Bake for 10-12 minutes, adjusting for gooey or crunchy cookies.
Let them cool slightly before enjoying—watch out for hot chocolate!