Set a rack in the middle of the oven and preheat to 350 degrees. Generously coat a 12-slot muffin tin with nonstick vegetable spray.
Into a large bowl, sift the flour, cocoa, baking soda, baking powder and salt together three times. In a mixing bowl, beat the butter and sugar together at high speed for 15 seconds, until combined. Add the eggs, one at a time, beating until each is incorporated. Continue beating until light and fluffy, about 6 minutes more. With the mixer on its lowest setting, beat in a third of the flour mixture. Beat in the buttermilk and vanilla, then another third of the flour. Beat in the coffee and then the remaining flour. Fill the cups of the muffin tin two-thirds full and bake for 15 minutes, or until the centers spring back when lightly pressed and a cake tester comes out clean. Set the pan on a rack to cool. With a small knife, carefully carve a 1-inch-round by 1-inch-deep plug out of the bottoms of the cupcakes-you're going to need the plug to refill the hole, so don't chuck it out. Fill with vanilla cream. Cut a 1/4-inch disk off the cake plug and cover the exposed cream. Dunk the cupcakes into the frosting to coat, then place on a rack, frosted side up. Transfer to the refrigerator for 20 minutes to set before serving.
Vanilla Cream Filling:
With an electric mixer, beat together the vegetable shortening and butter until blended. Turn the mixer down to its lowest setting and gradually add the confectioners' sugar. Turn the mixer back up and beat a high speed until light and fluffy, about 5 minutes. At a drizzle, gradually beat in the vanilla and corn syrup until the filling is the consistency of mayonnaise, about 2 minutes more. Scrape the vanilla cream frosting into a pastry bag fitted with a 1/4-inch plain tip.
Put the chocolate in a small bowl. In a small saucepan, over medium heat, bring the cream just to the simmering point. Pour the hot cream over the chocolate and, working from the center out, gently stir with a whisk to melt the chocolate and blend until smooth.
Courtesy of Wayne Harley Brachman, Retro Desserts, Harper Collins Publishers, 2000