1. Preheat oven to 350 degrees. Position a rack at the lower middle position. Combine the tablespoon of melted butter with the tablespoon of cocoa. Brush all over the inside of a 12-cup bundt pan.
2. Combine the remaining cocoa with the 6 ounces of chopped chocolate. Heat the 3/4 cup stout to nearly boiling. Pour over the chocolate mixture and allow to stand for five minutes. Stir until smooth, then stir in the sour cream until completely combined. Whisk the flour, salt, and baking powder together in a small bowl.
3. Using an electric mixer, beat the butter and brown sugar together on medium-high speed until fluffy. Add the eggs, one at a time, and beat until completely combined, scraping down the sides of the bowl occasionally. Reduce the speed to medium and add the flour mixture, a third at a time, alternating with the chocolate mixture, beating until completely combined and scraping the sides of the bowl after each addition.
4. Use a rubber spatula to scrape the batter into the prepared cake pan. Bake the cake for 45-50 minutes, until a cake tester or toothpick inserted into the center of the cake has only crumbs clinging to it. Cool in the pan for ten minutes, then invert onto a wire rack and allow to cool completely.

For ganache:

1. Click the link above for the recipe.