Chocolate and Hazelnut Dacquoise Cake

Ingredients:

• 1 and 1/3 tbsp. blanched hazelnuts
• 1.5 cups + 1/3 cup sugar
• 1 tbsp. potato starch
• Protein of 6 large eggs
• 1/4 teaspoon salt
• 1/4 cup whole milk
• 5 cups heavy cream
• 240 g dark chocolate, coarsely chopped, + chocolate shavings for decoration
• 1 tbsp. instant coffee powder

Preparation:

1. Position oven racks on the top and bottom racks and preheat the oven to 160°C (325°F). Spread the nuts on a baking sheet and toast in the oven for 12 to 15 minutes. Cool completely. Place 1 cup each of nuts, sugar, and cornstarch in a blender or food processor and puree. Transfer to a large bowl.
2. Reduce the oven temperature to 135°C (275°F). Line two large baking sheets with parchment paper. Using the bowl as a guide, draw three 7-inch (17.5 cm) circles on the paper with a pencil (two circles on one sheet of paper and one circle on the other). Turn the paper over so the drawing is facing down.
3. Place the egg whites, 1/2 cup sugar, and salt in a large bowl. Place the bowl over a double boiler (making sure it doesn't come into contact with the simmering water) and whisk until the sugar dissolves and the mixture is heated through, 2 to 5 minutes. Then remove the bowl from the boiler and beat the mixture with a mixer at medium-high speed until stiff and glossy, but not dry, about 2 minutes.
4. Using a silicone spatula, fold the milk and a quarter of the beaten egg whites into the nut mixture and mix until smooth. Then fold in the remaining beaten egg whites. Spoon the batter into 3 circles on the parchment paper and spread evenly with a spatula to fill them completely, without going beyond the edges. Bake for 1 hour 30 minutes, then rotate the baking sheets and continue baking for another 1 to 2 hours, until the cakes are golden and dry. (The cakes are ready when they easily peel off the paper.) Let them cool slightly on the baking sheets, then remove from the paper and transfer to a wire rack to cool completely.
5. Meanwhile, prepare the ganache: Pour 1 cup of heavy cream into a microwave-safe bowl and microwave for 2 minutes until very hot. Whisk in the chocolate and instant coffee until smooth. Cool the ganache to room temperature, then cover and refrigerate for at least 30 minutes until cold, thick, and spreadable.
6. Prepare whipped cream: Combine the remaining 4 cups cream and 1/3 cup sugar in a large bowl and beat with a mixer on medium speed until soft peaks form, 1-2 minutes. Finish whipping the cream by hand with a whisk until soft peaks form. Do not overbeat.
7. Place 2 cake layers on a baking sheet and spread half the ganache on each, all the way to the edges. Refrigerate for 15 minutes to set. (If the ganache is too thick and spreadable, warm it in the microwave in 20-second intervals to soften it.) Place one cake layer covered with ganache on a serving plate. Top it with 1 cup of whipped cream. Place the other cake layer covered with ganache on top and also top it with whipped cream. Top with the last cake layer and cover the top and sides with whipped cream. Chop the remaining 1/3 cup of hazelnuts and sprinkle them on top of the cake along with the chocolate shavings. Refrigerate the cake for at least 6 hours or overnight. Then serve.