I spent this past weekend celebrating my little sister, Eliot’s 30th birthday. We ate breakfast tacos and went to our first game at Fenway Park and laughed til we cried at least once. We also put on one hell of a birthday party in her Cambridge, MA, apartment, complete with lots of friends, a batch of salsa, and two of these Flourless Chocolate Hazelnut Cakes.

Eliot didn’t specifically ask for this cake. When we started talking about her birthday a few weeks ago, she said she’d be perfectly happy with Fluffernutter Sandwich Cookies or the Winning Hearts & Minds Cake we both love so much. After her summer in India, she’s discovered that maybe wheat isn’t for her, so her main request was that whatever I made be gluten-free. That was easy enough–I am all about flourless cakes. And chocolate and hazelnut is her favorite sweet flavor combination, so here we are.

Y’all, this Flourless Chocolate Hazelnut Cake is like a combination between a fudgy brownie and a jar of Nutella. Chocolate hazelnut overload! It’s very simple to put together and only has six ingredients: bittersweet chocolate, hazelnuts, eggs, butter, sugar, and salt. Yep, that’s all it takes to make this cake, but as with most recipes that have minimal ingredients, each one must be handled with care.

The chocolate has to be melted and cooled to room temperature.

The hazelnuts have to be toasted before having their skins removed and being blitzed into a fine meal.

The eggs need to be separated and the whites have to be whipped to stiff peaks.

Yes, all of that must be done before the batter can be put together. None of those steps are difficult or time-consuming, but they are completely necessary–no shortcuts here!

To make the batter, cream the butter and sugar together. Beat in the egg yolks and hazelnut meal before adding the chocolate. Stir 1/4 of the whipped egg whites into the batter before carefully folding in the rest 1/4 at a time. Pour it all into a buttered, parchment-lined cake pan and bake it just until a tester comes out clean.

Invert it onto a foil-lined plate.

Revert it onto a serving dish (or your favorite cake stand).

Eliot wanted her cake served with a dusting of confectioners sugar, but I prefer it with a puddle of ganache and some more toasted, skinned hazelnuts.

Slice it up and try not to eat the whole thing.

This Flourless Chocolate Hazelnut Cake is truly phenomenal. Chocolaty, hazelnutty (it’s a word today, okay?!), rich, but not too heavy–basically everything you want in a decadent dessert! Between testing, partying, and blogging, I’ve made five of these in the past week, and I am still having a hard time not sneaking bites and evening out edges.

Basically, what I’m saying is make this, and/or come take cake #5 away from me 🙂🙃

Happy birthday, Smel!

Flourless Chocolate Hazelnut Cake
makes one 9-inch cake

6 ounces bittersweet chocolate, chopped (I use Trader Joe’s Pound Plus Dark Chocolate)
6 ounces (1 heaping cup) whole raw hazelnuts 
6 large eggs, separated, room temperature
1/4 teaspoon Kosher or sea salt
6 ounces (1 1/2 sticks) unsalted butter, softened to room temperature 
1 cup granulated sugar

Garnish:
3 ounces (heaping 1/2 cup) whole raw hazelnuts
7 tablespoons heavy cream
5 ounces bittersweet chocolate, chopped

In a double boiler or the microwave, melt bittersweet chocolate. Set aside to cool to room temperature.

Preheat oven to 350F. Grease a 9-inch round cake pan with butter. Line the bottom with parchment and butter again. Set aside.

Place hazelnuts on a dry, rimmed sheet pan. Toast in the oven for 5-7 minutes, or until fragrant. Immediately transfer hazelnuts to a clean, dry, textured hand towel. Fold towel around the hazelnuts and then rub the towel with the palm of your hand. This will allow the hazelnut skins to loosen. This step does not have to be done perfectly.

Transfer hazelnuts to the bowl of a food processor. Pulse until a fine meal forms. Set aside.

Place egg whites and salt in a very clean, dry large mixing bowl. Use a very clean, dry electric mixer on medium-high speed to beat egg whites until stiff peaks form. Set aside.

In a separate large mixing bowl, use an electric mixer to beat butter until fluffy, about 1 minute. Add sugar and beat until combined. Add egg yolks three at a time, mixing to combine. Add hazelnut meal in two installments, followed by room-temperature melted chocolate.

Use a silicone spatula to add 1/4 of the whipped egg whites to the batter, stirring as much as necessary to get them to incorporate.

Continue adding the whipped egg whites in 1/4 increments, gently folding them into the batter.
Transfer batter to prepared pan. Bake 23-27 minutes, or until a toothpick inserted in the center comes out clean. Top may still be a bit jiggly, but it will set as the cake cools. Let cake cool completely in the pan on a rack.

Release the cake. Line a dinner plate with foil. Dip a small knife in warm water and slowly run it around the edge of the pan, dipping again as necessary, to loosen the cake. Place the dinner plate, foil-side down, on top of the cake pan. Holding on to both the pan and the plate, quickly flip them over. Remove the pan and the parchment. Gently place a serving plate, top-side down, onto the bottom of the cake. Holding tightly to both plates (but not so much as to crush the cake), quickly revert. Remove the foil-lined dinner plate.

Prepare the garnish. Place hazelnuts on a dry, rimmed sheet pan. Toast in the oven for 5-7 minutes, or until fragrant. Immediately transfer hazelnuts to a clean, dry, textured hand towel. Fold towel around the hazelnuts and then rub the towel with the palm of your hand. This will allow the hazelnut skins to loosen. Set aside to cool completely.

Warm cream in a small saucepan over medium-low heat, just until it simmers. Remove from heat and add chopped chocolate. Let sit undisturbed until chocolate looks soft. Stir with a fork until smooth. Spread or drizzle ganache over the cake. Dot with toasted hazelnuts, as desired.

Chocolate will set a bit after 20 minutes. Cake will keep covered at room temperature for up to two days, or in the refrigerator for up to three.