Preheat oven to 325 degrees F.
Prepare 3 8-inch round cake pans.
In a medium bowl stir together the cocoa powder, flour, baking soda, and salt; set aside.
In a small microwave-safe bowl combine unsweetened chocolate and sweet chocolate. Microwave, uncovered, on 100-percent power (high) for 1 minute; stir. Microwave, uncovered, for 30 seconds more; stir until smooth. Cool slightly.
In a 2-cup glass measure combine coffee crystals and boiling water, stirring to dissolve coffee crystals.
Add enough cold water to coffee to measure 1-1/2 cups. Stir in the 1/2 cup bourbon.
In a large bowl beat butter with an electric mixer on medium to high speed for 30 seconds. Add sugar.
Beat until combined, scraping side of bowl occasionally.
Add eggs, one at a time, beating well after each addition.
Beat in melted chocolate and vanilla. Alternately add flour mixture and coffee mixture to chocolate mixture, beating on low speed after each addition just until combined.
Pour batter into prepared pan, spreading evenly.
Bake about 20-25 minutes or until a toothpick inserted near center of cake comes out clean. Cool in pan on a wire rack for 15 minutes.
Remove cake from pan; cool completely on rack.
Brush top and side of cake with the 2 tablespoons bourbon.