- ¾ cup confectioners’ sugar
- ¾ cup hazelnuts toasted
- ½ cup cake flour
- ½ cup cornstarch
- 8 whole large eggs room temperature
- 2/3 cup granulated sugar
- 2 tablespoons melted butter — kept warm
- Preheat oven to 375°F.
- Spray two 9-inch round cake pans with nonstick cooking spray. Line with parchment circles. Spray again and flour. Tap out excess flour.
- In the bowl of a food processor, pulverize confectioners’ sugar and toasted hazelnuts until nuts are ground to a fine powder. Add the cake flour and cornstarch. Process for a few seconds to blend. Pour into a medium bowl and set aside.
- Place a large saucepan filled with 1 inch of water over medium-high heat and bring it to a simmer.
- In the bowl of an electric mixer using a handheld whisk, whisk eggs and granulated sugar constantly over the pan of simmering water until the eggs are very warm and foamy, and a thermometer placed in the bowl of eggs (not touching the bottom of the bowl) registers 110°F.
- Remove the bowl from the water and place it on the base of the electric mixer. Using the whip attachment on high speed, whip the egg mixture until it has tripled in volume and is cool to the touch. This will take several minutes. It should look like marshmallow fluff. As the batter falls from the whip, it should form a ribbon as it drops into the bowl before it dissolves into the rest of the batter.
- Place the melted butter into a small heat proof bowl and place it over the simmering water to keep it warm.
- Pour the egg and sugar batter into a very large mixing bowl.
- Sprinkle one third of the dry ingredients over the egg mixture and gently fold them in using a rubber spatula.
- Repeat sprinkling another one third of the dry ingredients into the egg mixture, gently folding it in. Sprinkle in the remaining one third of the dry ingredients and fold in gently. Do not overmix!
- Remove the butter from the water bath. Take a dollop of batter and whisk it into the butter to lighten it.
- Pour the lightened butter mixture over the batter and fold it in quickly and gently with a rubber spatula.
- Pour the batter evenly into the prepared cake pans.
- Bake for approximately 18 to 22 minutes, or until the cake is lightly browned and a small, sharp knife inserted in the center comes out clean. The cakes should spring back when you gently press them on top.
- Remove the cakes from the oven and using a thin, sharp paring knife, gently cut around the edge of each pan to separate the cake from the sides of the pan while it is still hot.
- Cool cakes in the pan until the pans feel lukewarm. Remove the cakes from the pans and place on cake racks to cool completely.
Makes 2 9-inch round layers