The Altitude Adjustment Section
This is a magnificent thing. It has three parts which can be made ahead of time and assembled when you have time. Did I mention it's magnificent?
Ingredients for the meringues
2 cups powdered sugar
1 1/3 cups finely ground hazelnuts
1 1/4 cups finely ground almonds
9 egg whites, room temperature
1/2 cup granulated sugar
Ingredients for the ganache
1 cup heavy cream
3 oz. milk chocolate, chopped
5 oz. bittersweet chocolate, chopped
Ingredients for the buttercream
2 cups granulated sugar
5 egg whites, room temperature
1 lb. unsalted butter, cut into pieces and softened
3 tbsp. coffee extract
2 cups sliced almonds, toasted
For the meringues:
Preheat oven to 250°. Line 2 baking sheets with parchment paper and draw three 8-inch circles on paper. Sift together powdered sugar, hazelnuts, and almonds into a medium bowl, pushing lumps through sieve, then set aside. Put egg whites in the clean bowl of a standing mixer and whisk on medium-low speed for 2 minutes. Increase speed to medium and whisk whites to soft peaks, about 2 1/2 minutes. Gradually add sugar while continuing to whisk, then increase speed to medium-high and whisk until whites form medium-stiff peaks, about 1 1/2 minutes. Transfer whites to a large bowl and carefully fold in 1/3 of nut mixture at a time with a rubber spatula. Divide meringue between parchment circles and gently spread out evenly. Bake in middle of oven, rotating positions hourly, for 4 hours. Remove and let cool completely.
For the ganache:
Heat cream in a medium saucepan and bring to a boil over medium heat. Remove from heat, add milk and bittersweet chocolates, and let sit for 1 minute. Whisk until smooth and set aside until thick enough to spread.
For the buttercream:
Combine 1/3 cup water and 1 1/2 cups of the sugar in a small saucepan and cook over medium heat until it reaches 250° on a candy thermometer. Put egg whites in the clean bowl of a standing mixer and whisk on medium-low speed for 2 minutes. Increase speed to medium and whisk whites to soft peaks, about 1 1/2 minutes. Gradually add remaining 1/2 cup sugar while continuing to whisk, then increase speed to medium-high and whisk until whites form stiff peaks, about 2 minutes. Carefully pour syrup into whites, whisking until cool, about 10 minutes. Add butter, bit by bit, whisking constantly until buttercream is shiny and fluffy, about 8 minutes. (Mixture may curdle, but will eventually come together.) Whisk in coffee extract and set aside.
Spread 1/3 of buttercream over each of 2 meringues. Spread ganache over remaining meringue. Layer meringues, placing the one with ganache in the middle. Spread remaining buttercream on sides of cake, then cover cake with almonds and refrigerate at least 5 hours. Then just stand around and take some pride.