Ingredients:
Meringue Layers (Dacquoise):
• 7 large egg whites, room temperature
• Pinch of fine salt
• 1 1/2 cups (300 g) granulated sugar
• 7 oz (200 g) raw cashews (or toasted hazelnuts/peanuts)
• 1 tbsp granulated sugar (for roasting nuts)
• 1 tbsp water
• 4 tbsp (about 30 g) cornstarch
Charlotte Custard Buttercream:
• 7 large egg yolks
• 1 cup (200 g) granulated sugar
• 200 ml (approx. 3/4 cup + 1 tbsp) whole milk
• 10.5 oz (300 g / 2 2/3 sticks) unsalted butter, softened to room temperature
• 1 tbsp cognac or dark brandy
• 2 tsp unsweetened Dutch-process cocoa powder
Directions:
Meringue Layers:
• Preheat your oven to 325°F (165°C).
• Toss the cashews with 1 tablespoon of water and 1 tablespoon of sugar.
• Spread on a rimmed baking sheet and roast for 8 to 10 minutes until pale golden and fragrant.
• Let cool completely, then coarsely chop (leave some distinct pea-sized crunchy bits rather than a fine meal).
• Line two large baking sheets with parchment paper.
• Using an 11-inch (28 cm) round cake pan or plate as a template, trace a circle onto each sheet of parchment with a pencil, then flip the paper pencil-side down.
• Ensure your stand mixer bowl and whisk attachment are completely dry and grease-free (wipe down with a lemon wedge and paper towel if needed).
• Add the 7 room-temperature egg whites and a pinch of salt.
• Beat on medium-low until foamy, then increase speed to medium-high.
• Gradually add the 300 g of sugar, one tablespoon at a time, beating for 1 to 2 minutes between additions until fully dissolved.
• Once all sugar is added, whip on high for another 10 to 12 minutes until stiff, ultra-glossy peaks form.
• Sift the cornstarch over the meringue. Add the cooled, chopped cashews.
• Using a large silicone spatula, gently fold using a figure-eight motion from the bottom up just until evenly distributed. Do not overmix.
• Divide the meringue evenly between the two traced circles on the prepared sheets, smoothing the tops and edges with an offset spatula.
• Bake at 310°F (155°C–160°C) with convection/fan for 10 minutes.
• Lower the temperature to 275°F (135°C–140°C) and bake for 10 minutes.
• Drop heat down to 215°F–225°F (100°C–110°C) and dry-bake for 2 to 2 1/2 hours until firm, crisp, and hollow-sounding when gently tapped.
• Turn off the oven, prop the door slightly ajar with a wooden spoon, and let the meringues cool completely inside to prevent cracking.
Charlotte Custard Buttercream:
• In a heavy-bottomed saucepan, whisk together the 7 egg yolks, 200 g sugar, and 200 ml milk until smooth.
• Set over low heat (or over a double boiler).
• Cook, whisking constantly and scraping the bottom, until thickened and just beginning to bubble gently at the edges.
• Remove immediately from heat and set the bottom of the pan in an ice bath to halt cooking.
• Let the custard cool to room temperature (it must match the butter’s temperature).
• In a clean stand mixer bowl fitted with the whisk or paddle attachment, beat the softened room-temperature butter on high speed for 4 to 5 minutes until pale, fluffy, and doubled in volume.
• With the mixer running on medium, slowly pour in the cooled custard base one tablespoon at a time until emulsified and velvety.
• Beat in the 1 tablespoon of brandy.
• Transfer about 1/3 of the buttercream to a separate bowl and sift in the 2 teaspoons of cocoa powder; stir until smooth.
Assemble:
• Gently peel the parchment off the meringue discs.
• Trim any uneven edges with a serrated knife, reserving the crunchy trimmings for crushed garnish.
• Place the first meringue disc onto a serving platter.
• Spread the light vanilla-brandy buttercream evenly over the top.
• Place the second meringue disc on top.
• Frost the top and sides with the chocolate Charlotte buttercream.
• Press the reserved crushed meringue crumbs and extra chopped toasted nuts all around the sides of the cake.
• Refrigerate for at least 3 to 4 hours (or overnight) so the buttercream sets firm.
• Let sit at room temperature for 15 minutes before slicing with a serrated bread knife.
