Adjust a rack one-third up from the bottom of the oven and preheat the oven to 180ºC . Butter an 8-cup0 loaf pan. Dust the pan with chocolate bread crumbs, tap over paper to remove excess crumbs, and set aside. Place both of the chocolates in the top of a double boiler over warm water on moderate heat until the chocolate is almost melted. Remove from top of the double boiler and stir until melted and snmooth. Set aside. In a small cup, stir in expresso, or coffee granules with the boiling water, and set aside. In a large bowl of an electric mixer, beat the butter until soft. Beat in the vanillaand sugar then the eggs, one at a time. Add the chocolate and beat to mix. On low speed, beat in half of the sifted dry ingredients, then the sour cream and expresso or coffee, and finally the remaining dry ingredients, scraping the sides of the bowl as necessary. Beat only until smooth. Turn batter into the prepared pan. Smooth the top. Bake for about 1 hour and 5 minutes, or until a cake tester gently inserted in the middle comes out dry. Remove from the oven and let stand 10 minutes. While standing the cake will settle down slightly, but it will beok. Cover the pan with a rack, turn the pan and rack upside down, remove the pan, and leet cake stand upside down to cool. Make the icing: Place teh chocolate in the top of a small double boiler and stir until melted ans smooth. Stir in the salt and sour cream. Carefully transfer the cooled cake to a serving board or flat tray. To keep the try clean while frosting, slip waxed paper strips under the cake. Spread the icing over the top and sides of the cake. Remove strips of wax paper. If the cake has been frozen or refrigerated, bring to room temperature before serving. Nutritional info per serving: 381 cal; 6g pro, 46g carb, 23g fat(49%), .4g fiber, 65mg chol, 239mg sodium