Step 1

For the candied pecans: Preheat the oven to 250 degrees F. Whisk the sugar, cinnamon and salt together in a bowl. In a separate bowl, whisk the egg white and water together until frothy. Toss the pecans in the egg white mixture, then add the sugar mixture and toss until the pecans are evenly coated. Spread the coated pecans on a baking sheet. Bake, stirring every 15 minutes, until the pecans are evenly browned, 1 hour.

Step 2

For the cake: Preheat the oven to 350 degrees F. Cut two 8-inch parchment circles and use to line the bottoms of two 8-inch cake pans.

Step 3

In a large mixing bowl, whisk together the four, white sugar, black and Dutch-process cocoa powders, baking powder, baking soda and salt. Add the buttermilk, brown sugar, oil, vanilla and eggs; beat with an electric mixer on medium speed for 2 minutes. Whisk in the hot coffee until completely incorporated--the batter will be quite thin.

Step 4

Pour the batter into the prepared pans. Bake until a cake tester inserted into the center of the cakes comes out clean, 30 to 35 minutes. Cool for 10 minutes, then slide an offset spatula around the edge of the pans and flip out the cakes. Cool on a rack for another 30 minutes.

Step 5

For the buttercream: Combine the egg whites and powdered sugar in a stand mixer fitted with the paddle attachment. Beat on medium speed for 5 minutes. (This helps dissolve all the sugar and prevents that grainy texture you often get with American buttercreams.) You will now have what looks like a really runny royal icing. Make sure your butter is soft. Set the mixer to medium and gradually add the butter, scraping down the bowl occasionally. Add the vanilla extract. Beat for 10 minutes on medium. Swirl in the butterscotch caramel.

Step 6

For the ganache: Heat the cream in a microwave just until boiling, 2 to 3 minutes. Pour the cream over the chocolate and allow to sit for 1 minute. Stir until the ganache is silky smooth--it look a bit curdled at first but will eventually come together. Leave the ganache on the counter to cool until it has reached the consistency of peanut butter. At this point it is ready to be used to frost the outside of the cake. (Makes 2 cups.)

Step 7

To assemble the cake: Remove the parchment paper from the bottoms of cakes. Split the cakes in half horizontally with a serrated knife (to make four layers). Place one layer on a serving platter. Spread a generous 3/4 cup buttercream over the layer to within 1/2 inch of the edge. Sprinkle 3 to 4 tablespoons candied pecans over the buttercream. Place a second cake layer over the first and repeat witht the buttercream and pecans. Continue with a third layer. Top the cake with the final layer and gently frost the outside with ganache.