Make cake layers:
Preheat oven to 300°F. and grease 3 9" pans. Line bottoms with rounds of parchment paper (Every baker should keep this on hand. Look for it with the wax paper not in the baking isle, they charge a lot more for it there.) and grease paper.
Finely chop chocolate and in a bowl combine with hot coffee. Let mixture stand, stirring occasionally, until chocolate is melted and mixture is smooth.
Into a large bowl sift together sugar, flour, cocoa powder, baking soda, baking powder, and salt. In another large bowl with an electric mixer beat eggs until thickened slightly and lemon colored (about 3 minutes with a standing mixer or 5 minutes with a hand-held mixer). Slowly add oil, buttermilk, vanilla, and melted chocolate mixture to eggs, beating until well combined. Add sugar mixture and beat on medium speed until just combined. Divide batter between pans and bake in the middle of the oven until a tester inserted in center comes out clean, 1 hour to 1 hour and 10 minutes. (Caution: this cake will rise A LOT. Do not over fill the pans, they should be no more than 3/4 full and maybe even a little less.)
Cool layers completely in pans on racks. Run a thin knife around the edges of the pans and invert layers onto racks. Carefully remove parchment paper and cool layers completely. Cake layers may be made 1 day ahead and kept, wrapped well in plastic wrap, at room temperature.
Transfer frosting to a bowl and cool, stirring occasionally, until spreadable (depending on chocolate used, it may be necessary to chill frosting to spreadable consistency).
Once the cakes are cooled and removed from pans cut into circles using a biscuit cutter. Spread 1 teaspoon of raspberry jam on to two cake layers and top with a third. Spread frosting over the top and sides. Cakes keeps, covered and chilled, 3 days. Bring cake to room temperature before serving. Garnish with fresh raspberries.
You could also save yourself a lot of trouble and make a full sized cake ;).