Pre-heat oven to 325* F. Butter two 8" round cake pans, line the bottoms with parchment paper and butter the parchment. Dust lightly with flour.
Place the chocolate and cocoa powder in a medium sized heatproof bowl. Pour hot coffee over the chocolate and cocoa and whisk until combined. Add the milk, whisk until smooth.
In another bowl, sift together flour, baking soda and salt. Set aside.
In the bowl of a mixer, fitted with the paddle attachment, beat the butter and both sugars on medium speed until light and fluffy about 3 minutes. Add the eggs, one at a time, beating well after each addition, then add the vanilla and beat until incorporated. Scrape down the sides and bottom of the bowl and mix again for 30 seconds.
Add the flour mixture in three parts alternating with the chocolate mixture, beginning and ending with the flour mixture.
Divide the batter between the prepared pans and smooth the tops. Bake for 35 to 40 minutes, rotating the pans halfway, until toothpick inserted comes out clean. Transfer the pans to a wire rack and let cool for 20 minutes. Invert onto rack and let cool completely.