Adapted from Butterlust

1/2 cup butter, softened
1 cup sugar
2 eggs
3/4 cup flour
3/4 cup natural cocoa powder
1/2 tsp sea salt, plus more for sprinkling
1 tsp baking soda
1 tbsp hot water
1 tsp vanilla
1 1/2 cups semi-sweet chocolate chips

1. Preheat oven to 350 degrees and line baking sheets with parchment paper.
2. In the bowl of a stand mixer, cream together the butter and sugar
3. Add the eggs, one at a time, mixing well between each one.
4. Add the cocoa powder, flour, and salt and beat until a dough forms – it should be the consistency of a thick brownie batter.
5. In a small bowl, dissolve the baking soda into the hot water. Add dissolved baking soda and vanilla and beat until well combined.
6. Stir in the chocolate chips with a spatula.
7. Refrigerate the batter for at least 30 minutes, up to overnight.
8. Use a cookie scoop to scoop out heaping tablespoons onto your prepared baking sheets and sprinkle with sea salt.
9. Bake for 10 minutes, or until edges are set.
10. Let cool completely on the baking sheets then transfer to a wire rack to cool.

And some cookie shaping science:
On the left are cookies that were jagged lumps of dough, then baked. On the right are cookies that were rounded balls of dough before baking. It makes a difference! Roll your dough.