Because the meringue requires a long, slow baking time, you might find it easiest to spread the assembly of this cake out over 2 days. The first day, make and bake the meringue and make the ganache, and the second day, assemble everything together and serve. The meringue does get softer after the cake is assembled, so for the best taste and texture, enjoy this cake the day it is made. (I do like it when it's slightly softer, however, so I like to assemble it a few hours before serving!)
32ozfresh raspberries(can substitute other berries or sliced fruit)
Toasted hazelnutschocolate shavings, or any other decorations of your choice
To Make the Hazelnut Meringue:
Preheat the oven to 200 F. Line two baking sheets with parchment, and trace two 8-inch circles on each piece of parchment, for a total of four 8-inch circles.
Combine the egg whites and the granulated sugar in the bowl of a large stand mixer, and whisk them together. Choose a small saucepan that lets you fit the base of the stand mixer snugly into the top of the saucepan—this is your makeshift hot water bath. (Alternately, you can use a different bowl or an actual bain marie and then transfer the mixture to a mixing bowl once it’s heated.) Add an inch of water to the bottom of the saucepan, and bring the water to a simmer.
Place the mixing bowl on top of the saucepan, making sure that the bottom isn’t in contact with the water, and heat the egg white mixture. Whisk frequently so that the egg whites don’t cook. Continue to heat the whites until they are hot to the touch, and when you rub a bit between your fingers, you don’t feel any grittiness from the sugar. Once the whites are hot, transfer the mixing bowl to your mixer and fit it with a whisk attachment.
Whip the egg whites on medium speed until foamy, then add the cream of tartar. Continue to whip the whites on medium-high speed until they are a shiny, stiff, voluminous meringue, and the outside of the bowl is no longer hot to the touch—this may take 10 minutes or more, depending on your mixer.
While you wait for the whites to whip, place the hazelnuts in the bowl of a food processor and process for a few seconds, until they are coarsely chopped. Add the powdered sugar, then process until the nuts are finely ground. Stop before the nuts start to clump together or get greasy!
When the whites are finished whipping, gently fold the finely ground nuts into the meringue. Divide the meringue between the four circles on the parchment paper, and spread them into even circles.
Bake the meringue circles at 200 F for 2 1/2 hours, rotating the pans halfway through for even baking. After 2 1/2 hours, turn the oven off and let the meringues sit in the oven until completely cool. They can be made a day in advance and kept in the cool oven until you're ready to assemble the cake.
To Make the Chocolate Ganache:
Place the chopped chocolate in a medium bowl and set aside. Pour the cream into a small saucepan and place it over medium heat. Bring the cream to a simmer, so that bubbles start to appear along the sides of the pan, but do not let it boil.
Pour the hot cream over the chopped chocolate, and let it sit for one minute to soften and melt the chocolate. Whisk the cream and chocolate together until the mixture is smooth and shiny. Press a layer of cling wrap on top of the chocolate and let it sit at room temperature to thicken and cool, until it is the texture of peanut butter. If you need to speed this process along, you can refrigerate it for 30-45 minutes. If it gets too hard, microwave it in short intervals until it is a spreadable consistency again.
To Make the Chocolate Whipped Cream and Assemble:
Combine the cream, cocoa powder, and powdered sugar in the bowl of a stand mixer fitted with a whisk attachment, and beat together until the cocoa powder holds medium peaks.
Assemble the cake by placing a meringue disc on your serving plate. Scoop a quarter of the ganache onto the disc, and spread it in a thin, even layer out to the edge. Place a quarter of the chocolate whipped cream on top, and spread it evenly. Place a ring of raspberries around the edge of the cake, then scatter a handful of raspberries in the middle of the cake as well. Top with a second meringue disc, and continue assembling the cake in this fashion until you've used all four meringue layers. On the top of the cake, after you've added the ganache and whipped cream, place a big pile of fresh berries in the center, along with a pinch of toasted hazelnuts, chocolate shavings, or any other garnishes you'd like.
This cake can be tricky to cut! If you want to serve it right away, the layers will be fairly crunchy and will crumble or crack. To serve it immediately, I recommend using either a very sharp serrated knife, and using light pressure while sawing the layers, or cutting through the individual layers with kitchen shears. My personal preference is to let it sit for an hour or two after assembly—the meringue will soften so the outside will still have a crunch, but it will be softer and easier to cut (although still a little messy!). Your best bet is to just accept that the slices won't look perfect, and that the taste will more than make up for a few cracked meringue layers!