Preheat your oven to 375 degrees. Grease an 8" round cake pan and line it with parchment paper.
Melt chocolate and butter in the microwave, then transfer to a mixing bowl.
Stir in sugar, vanilla, salt, eggs, and cocoa powder. Spread the batter in the cake pan and bake for approximately 25 minutes.
Cool for 5 minutes, then transfer to a serving plate. Let it cool before adding the chocolate ganache.