Almond-Hazelnut Espresso Torte

1. Prepare the Meringue

Preheat the oven to 250°F (120°C) and position the rack in the middle. Prepare a baking sheet by drawing a 13x10.5-inch rectangle on parchment paper, then place the parchment ink-side down on the sheet and lightly grease it.

2. Process Nuts and Cornstarch

In a food processor, combine 0.75 cup of toasted blanched sliced almonds, 0.5 cup of toasted and skinned hazelnuts, 1 tablespoon of cornstarch, and 0.125 teaspoon of salt. Process this mixture for 15 to 20 seconds until it's finely ground. Add 0.5 cup of sugar and pulse once or twice to combine.

3. Whip Egg Whites

In a stand mixer, whip 4 large egg whites with 0.25 teaspoon of cream of tartar on medium-low speed until foamy, about 1 minute. Increase the speed to medium-high and gradually add the remaining 0.5 cup of sugar. Continue to whip until the egg whites form stiff, glossy peaks, which should take about 2 to 3 minutes.

4. Fold Nut Mixture into Egg Whites

Gently fold the nut mixture into the egg whites in two batches until evenly incorporated. Spread the meringue into the prepared rectangle on the parchment paper and mist the surface lightly with water until it glistens. Bake the meringue for 1.5 hours, then turn off the oven and let it cool inside for another 1.5 hours. Remove it from the oven and let it cool to room temperature for about 10 minutes.

5. Prepare the Pastry Cream

In a small saucepan, heat 0.75 cup of whole milk over medium heat until it simmers. Meanwhile, in a separate bowl, whisk together 4 large egg yolks, 0.33 cup of sugar, 1.5 teaspoons of cornstarch, and 0.25 teaspoon of salt. Slowly add half of the hot milk to the yolk mixture, whisking constantly to temper the yolks. Return this tempered mixture to the saucepan and cook over medium heat, whisking constantly, until it thickens and bubbles, about 3 to 5 minutes. Transfer the pastry cream to a bowl, cover it with plastic wrap, and refrigerate for at least 2 hours or up to 24 hours.

6. Prepare the Buttercream

Once the pastry cream is chilled, warm it slightly in the microwave at 50% power, stirring every 10 seconds until it reaches a workable consistency. In a stand mixer, beat 16 tablespoons of softened unsalted butter on medium speed for 3 to 4 minutes until it is smooth and light. Gradually add the pastry cream in three batches, beating for 30 seconds after each addition. Finally, mix in 2 tablespoons of amaretto combined with 1.5 tablespoons of instant espresso powder, beating for another 5 minutes until the buttercream is smooth and fluffy.

7. Prepare the Ganache

In a small saucepan, heat 0.75 cup of heavy cream with 2 teaspoons of corn syrup over medium heat until it simmers. Pour the hot cream over 6 ounces of finely chopped bittersweet chocolate and let it stand for 1 minute. Stir the mixture until it is smooth and let it cool until it thickens slightly and mounds gently, about 5 minutes.

8. Assemble the Torte

Carefully invert the meringue onto a cutting board, peel off the parchment paper, and reinvert it. Trim the meringue to a 12x10-inch rectangle and cut it into four equal 10x3-inch rectangles. Spread 0.25 cup of ganache over each meringue rectangle and refrigerate them for 15 minutes. To assemble the cake, place one meringue rectangle ganache-side down on a serving platter and spread 0.5 cup of buttercream evenly over the top. Repeat this layering process, finishing with a layer of buttercream on the top and sides of the torte. Refrigerate the cake for at least 2 hours to set the buttercream.

9. Final Ganache Coat and Garnish

For the final coat, warm the remaining ganache slightly and pour it over the cake, spreading it evenly over the top and sides. Garnish the top with 12 toasted hazelnuts and press 1 cup of toasted sliced almonds onto the sides of the cake. Chill the torte uncovered for at least 3 hours or up to 12 hours before serving. To serve, transfer the cake to a platter and slice it with a hot, dry knife for clean cuts.