So, I have a weird history with Swiss Meringue Buttercream.
Don't get me wrong, we've gotten along alright. It's just...we've gotten along almost too well. I'm just waiting for something to go wrong every time I make it.
I have only made it twice, and maybe my butter has just been perfectly room temp each time or something, but I've never reached the despairing curdling stage.
The first time I made it, it was smooth and lovely. I thought I was doing it all wrong. But Sweetapolita affirmed that I was doing everything just swimmingly!
So...if yours curdles, I can't help you. But the aforementioned Sweetapolita can! Check out her post on all things SMB. It's been a lifesaver for many.
But don't let these curdle stories scare you away from making these cupcakes! The fluffiness of the sweet strawberry SMB is such a beautiful compliment to the dark cake, and the a strawberry on top is a refreshing topper on all that richness.
From what I've heard, you just have to keep whipping your buttercream. Brave out those curdles, and it will come together! And if you don't get any curdles...you're ok! You're not the only odd duck out there who looks like she knows what she's doing...but really doesn't.
Oh! If you're looking for a patriotic twist, add some blue foil liners, blueberries, blue sprinkles, colored sugar, or whatever to the top, and you've got yourself a mighty fine grill-out dessert. Just don't let that frosting sit in the heat too long.
Chocolate Cupcakes with Strawberry Swiss Meringue Buttercream
Yield: about 12 cupcakes
Ingredients for the cupcakes:
- 1 stick (1/2 cup, 8 tbsp.) unsalted butter, cut into 4 pieces
- 2 ounces bittersweet chocolate, chopped
- 1/2 cup (1.50 oz) Dutch-process cocoa
- 3/4 cup (3.75 oz) all-purpose flour
- 1/2 teaspoon baking soda
- 3/4 teaspoon baking powder
- 2 large eggs
- 3/4 cup (5.25 oz) granulated sugar
- 1 teaspoon vanilla extract
- 1/2 teaspoon salt
- 1/2 cup (4 oz) sour cream
Ingredients for the buttercream:
- 4 oz (about 1/2 cup) strawberries, fresh or frozen (if using frozen, thaw)
- 2 egg whites
- 1 1/2 sticks unsalted butter, at room temperature (but by no means softened)
- 1/2 cup granulated sugar
- small pinch of salt
- 1/2 teaspoon vanilla extract
To make the cupcakes, preheat the oven to 350 degrees F. Line a muffin pan with cupcake liners.
In a double boiler or a heat-proof bowl set over barely simmering water (not touching the water), combine the butter, chocolate, and cocoa. Heat until the butter and chocolate are melted and whisk until smooth (Do not allow the water to boil.). Set aside to cool until just warm to the touch.
In a small bowl, whisk together the flour, baking soda and baking powder. In a large bowl, whisk the eggs just to combine - then add the sugar, vanilla, and salt and whisk until smooth and fully incorporated. Add cooled chocolate mixture and whisk until combined. Add the flour and sour cream in three additions, beginning and ending with the flour. Whisk only until each addition disappears into the batter. Don't overmix, but make sure the dry and wet ingredients are fully combined before proceeding.
Divide the batter evenly among the 12 muffin cups and bake for about 18-20 minutes, or until a tester inserted into the middle of a cupcake comes out clean. Cool in the pan for 5-10 minutes and then set on a rack to cool completely before frosting.
To make the buttercream, hull the berries and cut into pieces. Puree the strawberries in a food processor or blender and pass through a fine-mesh sieve to remove the seeds; set aside.
Combine the egg whites, sugar, and pinch of salt in a heat-proof bowl set over barely simmering water (Make sure the bottom of the bowl doesn't touch the water and that steam doesn't get out, also be sure you keep the heat low so the water never boils.). Whisk constantly until the sugar has dissolved and the egg whites are hot to the touch - when you rub the mixture between your fingers, it should be smooth, without granules of sugar. This will take about 10-15 minutes. Remove from the heat and quickly wipe off any condensation from the bottom of a bowl with a towel. Transfer to the bowl of a mixer fitted with a whisk attachment. Whip on high speed until the egg whites form stiff, glossy peaks; about 5-10 minutes.
Cut the butter into 1 tbsp. pieces and add to the running mixer, one piece at a time, until completely incorporated. Continue beating on high speed. The mixture will first look like curdled soup; then, it will look like curdled cream; then, just when you're ready to cry and give up in despair, it will magically transform into wonderfully smooth buttercream. Trust me, this will happen. (It is possible that no curdling will occur after whipping in the butter, so don't despair if it becomes perfectly smooth right away. You're good; in fact, you're awesome! But 9 cases out of 10, you'll probably experiencing curdling. Time and patience, this isn't to be rushed.)
Switch to a paddle attachment and, with the mixer on low speed, add the vanilla. Beat for about a minute, until incorporated. Then, still on low speed, gradually add the strawberry puree and beat for 3-4 minutes, until the strawberries are completely incorporated and all the air pockets are gone. Decorate the cupcakes!
Also, Martha Stewart says that you can make the frosting up to 3 days in advance and store in an airtight container in the refrigerator - just bring to room temperature and re-whip with the paddle attachment until smooth, about 5 minutes. You can also store in the freezer for up to 3 months.
Sources: adapted from Confessions of a Tart, who adapted the buttercream from Martha Stewart and the cupcake from Cake on the Brain, originally from Cooks Illustrated