Preheat the oven to 350 degrees F. Grease a 12-cup Bundt cake and lightly coat with cocoa powder. Set aside. 

In a large saucepan, add the stout, chocolate, and butter. Heat on medium high and stir until the butter and chocolate are melted and all the ingredients are well-combined. Stir in the cocoa powder and mix well. 

Set aside and allow to cool to room temperature. 

Add in the eggs and beat well for about 3 minutes to combine. 

Beat in the brown sugar and granulated sugar. Fold in the yogurt until it is well-combined. 

Stir in the flour, baking soda, and salt. Mix until just combined. 

Pour the batter into the bundt cake and smooth out the batter. 

Bake the cake for about 50 - 55 minutes, or until a toothpick comes out clean. 

Once the cake is finished, remove the cake from the oven and allow to cool for 15 minutes. 

Tap the cake all around the sides and bottom to loosen the cake, then turn out onto a wire rack to cool completely to room temperature. 

While the cake is cooling, heat the stout for the ganache until it cooks down into a thick syrup. Add in the cream and heat while stirring until it is well combined and the mixture is steaming hot. Add in the chocolate and allow it to sit for 5 minutes for the chocolate to melt. Gently stir the mixture to combine. 

Pour the ganache over the cooled cake. 

The cake will keep in an airtight container at room temperature for about 7 days.