Brown Sugar-Hazelnut Cupcakes with Blackberry Buttercream Frosting

I don’t want to play favorites, but I’m going to have to: this here is my favorite cupcake to date. It’s actually my favorite cake (I’ve made it a few times before), but because I wasn’t in the mood to make a full-out layer cake (nor did I think it would be a good idea to have my favorite cake sitting in my apartment), I decided to just turn the cake into cupcakes.

What makes this cupcake so freakin’ good? It's a combination a few things: the crunchy layer of crushed hazelnuts on the bottom of the cupcake that provide a little textural surprise; the incredibly moist not too sweet cake (courtesy of yogurt and brown sugar); and the satiny lavender-colored blackberry buttercream frosting (frosting that is purple through natural means obviously gets bonus points in my book). Add them up and you get one killer cupcake.

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Brown Sugar-Hazelnut Cupcakes with
Blackberry Buttercream Frosting
(makes 8 cupcakes)

For the Brown Sugar-Hazelnut cupcakes:
¼ cup hazelnuts
1 tablespoon sugar
¾ cup all-purpose flour
1 teaspoon baking powder
1/8 teaspoon salt
¼ cup low-fat yogurt
¼ cup milk
½ teaspoon vanilla
3 tablespoons butter, room temperature
½ cup packed light brown sugar
1 egg, room temperature

For the Blackberry Swiss Meringue Buttercream frosting:
4 ounces fresh blackberries
1 tablespoon sugar
[Alternately, 2 tablespoons blackberry jam in place of the blackberries + sugar]
2 egg whites
¼ cup + 2 tablespoons sugar
1 stick (8 tablespoons) unsalted butter, cut into small pieces and at room temperature

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Cupcakes:

Heat an oven to 350 F. Line 8 wells of a muffin pan with cupcake papers.

Put the hazelnuts and sugar into the bowl of a mini chopper and pulse until the nuts are ground – you want some texture so do not grind them too finely. Evenly distribute the ground nuts between the lined wells of the pan and set the pan aside.

In a small bowl, sift together the flour, baking powder, and salt. Set aside. In another bowl, whisk together the yogurt, milk, and vanilla. Set aside.

In the bowl of a mixer fitted with the paddle attachment, cream the butter and light brown sugar on medium speed until light and fluffy, 2-3 minutes. Scrape down the sides of the bowl, add the egg, and mix until combined.

Add half of the flour mixture, all of the yogurt mixture, and then the remaining flour, mixing on medium speed after each addition until just combined.

Distribute the batter between the cups. Bake until lightly golden around the edges and a toothpick comes out clean, 16-18 minutes.

Frosting:

Slice 4 berries in half lengthwise and set them aside.

Puree the remaining berries along with the sugar. Strain the blackberry puree through a fine-mesh sieve into a small saucepan. Gently simmer the puree over medium-low heat until it is thick and reduced to about 2 tablespoons; this will take 10-12 minutes. Remove the saucepan from the heat and set it aside to cool.

Put the sugar and egg whites in the bowl of a standing mixer. Bring 2 inches of water to a simmer in a medium saucepan and set the mixer bowl on top of the pan. Whisk the egg white mixture until it is 130 F – the mixture will turn thick and white, and this should take about 3 minutes.

Transfer the bowl to a standing mixer fitted with a whisk attachment. Whip the egg white mixture on high speed until it is cool, thick, and glossy, about 7 minutes. Reduce the speed to medium-high and add the butter a few pieces at a time, making sure they are fully incorporated before the next addition. After all the butter has been added, continue beating the frosting until it comes together – this will take a minute or two.

Add the reduced blackberry puree (or jam) and mix to combine.

Frost the cupcakes and top each with a berry half.