For a delicious chocolate cake, make this decadent treat for your home!
Preheat oven to 325 degrees.
To make the cake: Sift together sugar, flour, salt, and baking soda in a bowl. Pour the hot coffee over finely chopped chocolate, and allow chocolate to melt completely.
In a separate bowl, whisk together the eggs and vegetable oil until well blended, followed by sour cream, vanilla, and coffee/chocolate mixture. Stir this liquid mixture into the dry ingredients by thirds, stirring well after each addition until completely blended. Divide the batter evenly between 2 buttered and floured parchment-lined 9-inch cake pans. Drop each cake pan once onto the counter from a height of 3 inches, to remove any large air pockets, which could cause holes or tunnels in the baked cake layers. Bake in the preheated oven for 30-40 minutes, until the cake springs bake slightly when gently tapped in the center or a cake tester inserted in the center comes out clean. Remove immediately to cooling racks, and allow to rest for 5 minutes before turning out of the pans. To unmold, run a flat-edged knife or spatula between the cake layers and the sides of the pans. Turn the pans facedown onto the cooling rack, and carefully lift them off. Allow cakes to cool completely before peeling off the parchment layer and frosting them.
To make the frosting: Heat the cream, butter, sugar, and salt in a heavy saucepan until the butter is melted. Add the chocolate, and cook over very low heat, stirring constantly, just until the chocolate is melted and the mixture is smooth. Remove from heat, and blend in the coffee and vanilla. Transfer the frosting to a bowl to cool, stirring occasionally, until it is of a spreading consistency — about 1 hour, depending on the temperature of the kitchen. (If your kitchen is very warm, move the frosting to a cooler area to cool and thicken, but do not refrigerate or chill over ice water. Chocolate and butter solidify at different temperatures, and harsh chilling could cause the frosting to separate and turn grainy.)
To assemble the cake: When the frosting is of a spreading consistency and the cake layers are completely cooled, put 1 cake layer on a serving platter, bottom side up, and frost the surface thickly. Top with the other layer, bottom side down, and frost the top and sides. For best results, allow the cake to sit for 2 or more hours before slicing. Store covered at room temperature.