1/2 cup (4-ounces) unsalted butter, at room temperature
1/2 cup (3 3/4-ounces) firmly packed brown sugar
4 -- egg yolks
1 teaspoon pure vanilla extract
3 tablespoons whole milk
1/4 teaspoon fine sea salt
4 -- egg whites
3/4 cup (5 1/4-ounce) granulated sugar
1 teaspoon pure vanilla extract
1/4 cup (1-ounce) toasted and coarsely chopped Hazelnuts (See Toasted Nuts, below)
2 teaspoons turbinado sugar
-- Fresh berries, for serving, optional
First, make the honey custard. Heat the milk over low heat in a small saucepan until hot but not boiling. Meanwhile, thoroughly whisk together in a small bowl the egg yolks, honey, and salt, and then whisk in the cornstarch. Slowly whisk one third of the hot milk into the yolk mixture. Pour this mixture back into the saucepan with the hot milk and gently cook over medium-low heat, whisking steadily, until the mixture begins to thicken and has been bubbling for roughly 1 minute. You will need to stop whisking for a moment to check if it is bubbling. Strain the mixture through a fine mesh sieve into a clean bowl and whisk in the butter until melted. Place a piece of plastic wrap directly on the surface of the custard and refrigerate at least until cool, about 1 hour, or keep in an airtight container in the refrigerator for up to 5 days.
To make the cake, center an oven rack and preheat the oven to 350F. Grease 2 (8-inch) round cake pans and line bottoms with parchment paper circles
In a small bowl, sift together the flour, baking powder, cinnamon, and salt and then whisk the ingredients by hand to ensure they are well mixed.
Using a stand mixer fitted with the paddle attachment, combine the butter and brown sugar together on medium speed until smooth. Add the egg yolks two at a time, blending well between additions. Combine the milk and the vanilla in a separate cup. On low speed, stir in the flour mixture in three additions, alternating with the milk in two additions, beginning and ending with flour mixture. After each addition, mix until just barely blended and stop and scrape the bowl.
Divide the thick batter between the prepared pans (there will be approximately 7 3/4 ounces per pan) and spread it evenly out to the edges of the pans. The batter will just barely cover the bottom of each pan. Set the pans aside while you prepare the topping.
To make the topping, put the egg whites and salt into the clean bowl of a stand mixer fitted with the whisk attachment. Whip on low speed until frothy and then add the cream of tartar. Gradually increase the speed to medium-high, whipping until the whites form soft peaks. With the mixer on low speed, slowly add the granulated sugar in a steady stream. Raise the mixer speed again to medium-high and continue whipping until the whites just begin to hold firm, glossy peaks. Fold in the vanilla. Spread even amounts of the meringue on top of the cake batter (approximately 5 ounces per pan) and sprinkle with the hazelnuts and turbinado sugar.
Place the cakes in the middle of the oven and bake until the tops are lightly browned and the cakes have shrunk just slightly away from the sides of the pan, 30 to 35 minutes. Remove the cakes to cool on a wire rack for 20 minutes before removing them from the pans.
To assemble the cake, place one of the cake layers, meringue side up, onto a cake plate. Don’t be nervous about the peaks and valleys of the meringue; this is part of the allure of the cake! Spread the honey cream onto the cake. Place the second layer on top, meringue side up. Serve promptly or refrigerate until ready to serve. This cake is great served with fresh berries either on the side, in the middle, on the top, or all of the above.
If you choose to sandwich this cake with jam, it can be kept in an airtight container at room temperature. If filled with the honey cream, it needs to be kept in an airtight refrigerated container. Either way, the cake is best the day it is made but keeps for up to 2 days.
Toasting Nuts: Toasting nuts not only brings out their flavor, it also makes it easier to remove the skins, especially from hazelnuts, one of my favorite ingredients. To toast nuts, spread them evenly out on a baking sheet and place them in a 350F oven. Alternatively, place them in a heavy skillet over medium-high heat. Either way, give the pan a shake (more frequently if using a skillet) to ensure the nuts don’t burn. Once the nuts smell fragrant and begin to brown (about 10 minutes), remove them from the heat. They’ll continue to brown a bit as they cool. To remove hazelnut skins, flip the nuts onto a clean kitchen towel and rub them inside the towel as if you were trying to dry them off. Some skins will cling to the nuts, but most will come off.