Last week was Paul's birthday.
Preheat the oven to 325°F.
Grease and flour two 8" round by 2" deep cake pans. Sift together or whisk the dry ingredients through a strainer into a large mixing bowl.
Combine the boiling water and the tea bags. Let stand five minutes, then remove the bags and return the water to a boil.
Combine the oil, buttermilk, boiling water and vanilla in a medium bowl or large measuring cup. Add to the dry ingredients and mix well. Scrape the sides and bottom of the mixing bowl, then beat in the eggs, one at a time. Mix on medium speed for another 2 minutes or until smooth.
Divide the batter between the two pans and bake for about 50 minutes, or until the cakes spring back when lightly touched or a toothpick inserted in the middle comes out with only a few moist crumbs attached.
Let cool completely on a wire rack, then turn out of pans and wrap tightly in plastic wrap. Place in the freezer for at least 1 hour before assembling the cake.
For the Mousse:
Melt chocolate, cocoa powder, espresso powder, water, and brandy in medium heatproof bowl set over saucepan filled with 1 inch of barely simmering water, stirring frequently until smooth. Remove from heat.
Whisk egg yolks, 1 1/2 teaspoons sugar, and salt in medium bowl until mixture lightens in color and thickens slightly, about 30 seconds. Pour melted chocolate into egg mixture and whisk until combined. Let cool until just warmer than room temperature, 3 to 5 minutes.
In bowl of mixer fitted with whisk attachment, beat egg whites at medium-low speed until frothy, 1 to 2 minutes. Add remaining 1 1/2 teaspoons sugar, increase mixer speed to medium-high, and beat until soft peaks form when whisk is lifted, about 1 minute. Detach whisk and bowl from mixer and whisk last few strokes by hand, making sure to scrape any unbeaten whites from bottom of bowl. Using whisk, stir about one-quarter of beaten egg whites into chocolate mixture to lighten it; gently fold in remaining egg whites with rubber spatula until a few white streaks remain.
In now-empty bowl, whip heavy cream at medium speed until it begins to thicken, about 30 seconds. Increase speed to high and whip until soft peaks form when whisk is lifted, about 15 seconds more. Using rubber spatula, fold whipped cream into mousse until no white streaks remain.
For the Ganache:
Heat the heavy cream in the microwave until boiling (watch carefully!). Immediately pour it over the chopped chocolate and let stand for about 30 seconds before carefully whisking until smooth and glossy. Let stand at room temperature until cooled before pouring over the cake.
To Assemble the Cake:
Remove chilled cake layers and slice each layer evenly in half with a serrated knife. Place one layer on a cardboard round set on a wire rack placed in a baking sheet. Carefully spread 1/2 of the mousse evenly over the layer. Top with another cake layer and once again smooth with the remaining mousse. At this point, you may make a ring out of a strip of aluminum foil to wrap around the cake in order to keep the mousse contained within the cake layers. Top with a third cake layer and return the cake to the fridge to set for at least 1 hour before topping with the ganache (Please do not rush it like I did - the cake will turn out much more beautiful if you are patient!).
Once chilled, pour a generous portion of the ganache over the top of the cake and allow it to run down the sides. Use an offset spatula to smooth it over the tops and sides. Decorate with any remaining ganache. If you chill the leftover ganache for about 30 minutes, its texture will change to resemble the soft, silky insides of a truffle and you will be able to pipe it into pretty shapes all over the cake.
Return the assembled cake to the fridge to chill for at least 1-2 more hours before serving.