To Make The Brownie Batter:

1. In a saucepan, melt the butter for the brownie batter.
2. In a mixing bowl, add the chocolate chips. 
3. Once the butter is melted, pour it over the chocolate chips and stir together. Mix until the chocolate has completely melted and combined.
4. Add the cocoa powder, white sugar, eggs, and vanilla. Mix together until combined and thick. Pour in the flour and salt. 
5. Fold together all the ingredients once more until the brownie batter is completely smooth. Set aside this batter.
6. Preheat the oven to 350°F.

To Make The Chocolate Chip Batter:

1. Melt the stick of butter for the chocolate chip batter until browned and nutty.
2. Pour this into a separate large mixing bowl, adding the white sugar, brown sugar, and vanilla extract. Mix together until combined.
3. Add in the flour, baking soda, baking powder, and salt. Fold the dry ingredients into the wet until a thick batter is formed.
4. Fold in the chopped chocolate chunks until evenly distributed.

Assemble and Bake:

1. In a baking dish lined with parchment paper, pour in the brownie batter. Spread evenly as the bottom layer.
2. Drop large tablespoonfuls of the chocolate chip cookie dough on top of the brownie batter.
3. Use a knife to create a swirl within the batter and mix the chocolate and brownie batters together.
4. Bake in the oven for 25 to 30 minutes, or until a toothpick inserted comes out clean.
5. Top these brookies with sea salt when they come out of the oven and let cool completely.
6. Once cooled, cut into squares and serve!