In a bowl combine the flour (180g), cocoa powder (25g), Dutch process cocoa powder (7g), salt (4g), baking soda (3g), baking powder (6g), and chocolate chips (340g) and whisk together.
In the bowl of a stand mixer combine the softened butter (113g), brown sugar (100g), and granulated sugar (50g) and mix on medium until whipped and fluffy.
Add the molasses (21g), vanilla (3g), and egg and combine.
Alternating and with the stand mixer on low-ish, add the flour mixture and the stout until all the flour mixture is added and most of the stout. (I added the full amount, and it worked, but it was a very loose dough.) If the consistency seems right, stop adding stout.
Scrape down the sides of the bowl, cover with plastic wrap, and refrigerate for 1-2 hours.
Heat oven to 350℉ / 175℃.
Line a half-sheet pan with parchment paper. Using a 1-tablespoon scoop, scoop out 10-12 cookies per pan, keeping some separation as these will spread.
Bake for 15-17 minutes, turning half way through.
Remove from oven and remove to wire rack and sprinkle with a pinch of finishing salt.