1. Preheat the oven to 375°F (190°C). Line a baking sheet with baking parchment and set aside.

 

2. Add the butter and brown sugar to a large bowl and mix on high speed until light and fluffy. Add the vanilla extract and mix in. Mix the flour with cocoa powder, baking powder, and salt and add to the mixing bowl – mix until just combined. Shape the dough into 16 walnut-sized balls, flatten them a bit and place on the baking sheet with some space in between. Use a fork to press a criss-cross pattern into the cookies and bake them for 5 minutes. Reduce the heat of the oven to 300°F (150°C) and continue baking the cookies for another 15-18 minutes until the cookies are firm but not hard. Take out of the oven and let cool down on a wire rack.