Preheat oven to 375 degrees F (190 degrees C). Place bacon in a large, deep skillet. Cook over medium-high heat until evenly brown. Drain, crumble and set aside.
In a large bowl, stir together the flour, 3/4 cup cocoa powder, sugar, baking soda, baking powder and salt. Make a well in the center and pour in the eggs, coffee, buttermilk and oil. Stir just until blended. Mix in 3/4 of the bacon, reserving the rest for garnish. Spoon the batter into the prepared cups, dividing evenly.
Bake in the preheated oven until the tops spring back when lightly pressed, 20 to 25 minutes. Cool in the pan set over a wire rack. When cool, arrange the cupcakes on a serving platter. Frost with your favorite chocolate frosting and sprinkle reserved bacon crumbles on top. Dust with additional cocoa powder.