Grease and flour two 8x1-1/2-inch round baking pans. Set aside.
In a small bowl, combine flour, baking powder, soda, and salt; set aside. In a large bowl, beat sugar and shortening with electric mixer on medium speed until combined. Beat in eggs and vanilla, beating until light. Stir in melted chocolate and sour cream. Add flour mixture and milk alternately to chocolate mixture, beating on low speed after each addition until just combined. Pour batter into prepared pans.
Bake in a 350 degree F oven about 30 minutes or until tops spring back when lightly touched. Remove from oven; cool on wire racks for 10 minutes. Remove from pans; cool completely on wire racks.
Meanwhile, prepare No-Cook Fudge Frosting. (If you like, stir cognac or brandy into 1/2 cup of the cooled frosting). Place one cake layer on cake plate. Spread the cognac-flavored or 1/2 cup plain frosting over top of one layer. Place other layer on top. Frost top and side with remaining frosting. Makes 12 servings.
In a large bowl, stir together powdered sugar and cocoa powder. Add butter, boiling water, and vanilla. Beat with an electric mixer on low speed until combined. Beat for 1 minute on medium speed. Cover and cool for 20 to 30 minutes or until of spreading consistency.