Preheat the oven to 325 degrees. Line your cupcake pans with liners (this makes 36, so if you have three pans, use them. Otherwise, they'll have to take turns.)
Place chopped chocolate in a bowl and pour hot coffee over it. Stir and allow to sit until melted, stirring occasionally.
In a large bowl sift together the sugar, flour, cocoa powder, soda, baking powder, and salt.
In the bowl of an electric mixer, beat the eggs until they're thickened slightly and pale yellow (about 3 minutes). With the mixture on low speed, slowly pour in oil, buttermilk, then vanilla, then melted chocolate mixture. Turn the speed up slightly, beating until well combined.
Add the flour mixture in three separate additions, beating well after each addition.
Divide cupcake batter evenly, being sure to fill no more than 2/3 full. I have a terrible habit of overfilling cupcakes and these raised a lot so all of mine overflowed. (It's so painful to have to tear off the overflow edges and eat them...it's the price the baker has to pay).
Bake cupcakes for 25-35 minutes or until toothpick inserted in the center comes out clean. Allow to cool in the pans then remove. Allow to cool completely before frosting.