Grease and flour three 8-inch cake pans, then line the bottom with a piece of parchment paper cut in a circle to fit. Set aside.

Add the beer and butter to a large, heavy bottom saucepan. Warm on medium until the butter melts then remove from the heat and gently whisk in the cocoa powder until smooth. Cool to room temperature.

In a large mixing bowl combine the flour, sugar, baking powder and salt. Whisk until blended and set aside.

In a separate large mixing bowl beat together the eggs and sour cream.

Gently add the cocoa mixture and blend on low until combined.

Add the flour mixture on low speed, scraping down the sides as needed. Mix on medium for 1 minutes.

Divide the batter between the three prepared cake pans. If you have a kitchen scale, each one should weigh a little over 2 pounds. Bake for 35 to 40 minutes or until a toothpick comes out almost clean, or at least not wet. Crumbs are okay. Do not over-bake.

Cool the layers on a rack for ten minutes, then remove the cake from the pans and continuing cooling on the wire rack until no longer warm.

Frost as desired and store leftovers in the refrigerator.

Add the chopped chocolate to the top of a double boiler set over barely simmering water. Stir until melted and smooth. Set aside to cool, but still pourable.

While the chocolate is melting, combine the coffee, water and cocoa in a small saucepan. Heat on low and whisk until smooth and slightly thickened. Remove and set aside to cool to room temperature.

Add the butter and 1 cup of the confectioners' sugar to a large mixing bowl. Beat until the butter is light and fluffy. Add the cooled, melted chocolate, vanilla and salt. Blend on medium until smooth. Add the cooled cocoa mixture and beat until incorporated. Gradually add the remaining 3 cups of confectioners' sugar, blending until smooth.