Preheat oven to 350° F
Use an 11 or 12 cup capacity bundt pan (or an equivalent). Prepare it generously with butter and flour. (see notes above about baking the cake in other sized pans)
In a small to medium-sized saucepan, add the beer and simmer until it has been reduced to 1 cup. Remove from the heat, add the butter, and stir until it has melted.
Add the cocoa powder, stirring until the mix is smooth
Set aside to cool, stirring occasionally
(Note: You can make the chocolate/butter/beer mix a day or two before and store it in the fridge. When ready to use, warm it up ever-so-slightly and stir until smooth)
In a medium bowl, whisk together the flours, brown sugar, baking soda, and sea salt. Set aside.
In the bowl of your mixer, add the eggs, yogurt, and maple syrup.
Mix until it's blended and uniform in appearance.
Gradually add the (cooled) beer mix, and blend until combined.
Add the flour mix, and this time by hand, fold until just blended, using as few strokes as possible.
Transfer the batter to the prepared pan and bake for 40 - 45 minutes (if using the bundt pan), or until a knife inserted in the center comes out clean.
Remove from the oven, and turn out onto a cooling rack after seven minutes.
(Note: You really don't want to over bake this cake - err on the slightly moist side)
Melt the chocolate, heavy cream, and coffee in the top of a double boiler over simmering water until smooth and warm, stirring occasionally.
Drizzle over the top of cooled cake
When the cake is completely cool, drizzle the ganache over the top and let it set
Just before you're ready to serve, sprinkle the cake with a bit of flaky sea salt.
(Note: If you sprinkle the sea salt on ahead of time, you'll end up with little divots)