Preheat oven to 325°. Line bottoms of 3 greased 8-in. square baking pans with parchment; grease the paper.
Place chocolate in a small bowl. Pour hot coffee over chocolate; stir with a whisk until smooth. Cool slightly.
In a large bowl, beat eggs on high speed until lemon-colored. Gradually add sugar, oil, vanilla and the chocolate mixture, beating until well blended. In another bowl, mix flour, cocoa, baking soda, baking powder and salt; add to chocolate mixture alternately with buttermilk, beating well after each addition.
Transfer to prepared pans. Bake 30-35 minutes or until a toothpick inserted in center comes out clean. Cool 10 minutes before removing from pans to wire racks; remove paper. Cool completely.
For ganache, place chocolate in a large bowl. In a small saucepan, bring cream and corn syrup just to a boil. Pour over chocolate; stir with a whisk until smooth.
Let stand at room temperature to cool and thicken slightly, about 45 minutes, stirring occasionally. (Mixture will be very soft, but will thicken when spread onto cake.)
Place 1 cake layer on a serving plate; spread with 1/3 cup ganache. Repeat layers. Top with remaining cake layer. Spread remaining ganache over top and sides of cake.
TWO-LAYERED DEEP & DARK GANACHE CAKE & CUPCAKES: Prepare cake as directed, using 12 paper-lined muffin cups and 2 greased and parchment-lined 8-in. square baking pans. Fill muffin cups three-fourths full; bake at 375° for 15-17 minutes or until a toothpick comes out clean. Divide remaining batter between prepared cake pans. Reduce oven setting to 325°; bake cake layers as directed. Yield: One 2-layered cake and 1 dozen cupcakes (24 servings).