Preheat an oven to 350 F. Prepare a 9” springform pan by greasing it with softened butter. Dust the inside of the pan with cocoa powder. Line the inside of the pan with a round piece of parchment paper.
Cut the butter into a dice. Place the butter and chocolate chips over a double boiler and heat until completely melted. Allow the chocolate to cool while you whip the eggs. The chocolate mixture should not be hot but warm.
In the meantime, whip the eggs, both sugars, and vanilla in the bowl of a stand mixer for 10-12 minutes at the highest speed. The mixture should be light and fluffy.
While the eggs are whipping, sift the all-purpose flour through the sea salt together. Doing so will ensure the cocoa powder has no lumps.
Add the cooled chocolate to the egg mixture. Carefully fold the chocolate into the eggs using a spatula. The chocolate should be streaked throughout and not thoroughly mixed.
Add the dry ingredients. Carefully fold the dry ingredients in until entirely mixed being careful not to deflate the eggs.
Pour the brownie batter into the prepared pan. Sprinkle the top of the brownie cake with one tablespoon of granulated sugar. Bake for 40-45 minutes. A toothpick inserted into the center of the cake should come out with some crumbs but not be completely dry. Err on the side of slightly underbaked so that the cake will stay fudgy.
Allow the cake to cool completely before cutting into sixteen slices.
Tips
Be sure to whip the eggs for the entire length of time. The fluffy egg mixture is what is responsible for this cake’s crackly top.
Err on the side of underbaking the cake. A toothpick inserted should not come out completely clean but with a few fudgy crumbs (and not be completely dry). The cake will continue to bake outside of the oven. If the toothpick comes out with liquid batter, bake the brownie cake longer.
