These were supposed to be Cherry Cupcakes with Lime Buttercream (riff on Cherry Limeade) - but sometimes recipe development just doesn't work out as planned. It's all good because these cupcakes are wonderful! A light, fluffy white cake flavored with lime juice and zest giving them a bright, fresh zing.
I've always wanted to try making Swiss Buttercream so I was thrilled to finally get the chance. I love regular buttercream frosting, and cream cheese frosting but am not a big fan of high-ratio shortening filled frosting. Frosting, no matter what kind, can sometimes taste cloyingly sweet and overpower the cake.
Swiss Buttercream is light and fluffy, almost like whipped topping, but it's completely stable. It won't melt like whipped cream and holds it's gorgeous smooth ribbons and shiny appearance. This could be the perfect filling for macarons - can't wait to try it!
The buttercream is made by combining granulated sugar and egg whites over a double-boiler of gently simmering water. Once the sugar is dissolved and the egg whites reach 160 degrees, you whip them into to stiff peaks. Next add flavoring and butter, just a little at a time. There are times when you think the frosting has curdled but then it magically finds it's way and you are left with a smooth, shiny, buttery frosting.
Lime Cupcakes with Swiss Lime Buttercream
for the cupcakes:
3 large egg whites, room temperature
1/3 cup whole milk, room temperature
1 teaspoon pure vanilla extract
1 1/2 cups cake flour
3/4 cup granulated sugar
2 teaspoons baking powder
1/2 teaspoon salt
8 tablespoons (1 stick) unsalted butter, cut into 8 pieces
1 tablespoon lime zest
2 tablespoons lime juice
for the Swiss Lime Buttercream Frosting:
1 cup granulated sugar
4 large egg whites
Pinch of fleur de sel (or other coarse salt)
1 1/2 sticks unsalted butter, room temperature
3 - 4 tablespoons fresh lime juice
1/4 cup confectioners' sugar (only if needed to reach the desired consistency and sweetness)
Garnish with lime slices and zest if desired
To prepare the cupcakes:
Line a cupcake pan(s) with paper liners. You will need 12 or 13 lines. Preheat oven to 350 degrees.
In a large measuring cup with a pouring spout, whisk together the egg whites, milk, and vanilla. Set aside.
Using a stand mixer fitted with the paddle attachment, blend the flour, granulated sugar, baking powder and salt on low for about 30 seconds. With the mixer running, add the butter 1 piece at a time until incorporated and the mixture resembles moist crumbs.
Scrape the batter into a large Ziplock bag and snip off one corner with scissors. Pipe the batter into the liners, dividing evenly between 12 or 13 cupcakes. I made 12 but they were a little big and over the edge, 13 would be about perfect. Bake in a 350 degree oven for 18-20 minutes. Test the cupcakes with a toothpick inserted in the center. If it comes out clean, they are done.
Cool the cupcakes in the pan for 10 minutes. Transfer cupcakes to a rack and let cool completely before icing.
To prepare the Swiss Buttercream:
Combine the sugar, egg whites and salt in a heatproof stainless bowl or the pan of a double boiler. Set the bowl over a pot of simmering, not boiling, water. Whisk the egg whites until the mixture reaches 160 degrees on an instant read thermometer and the sugar has dissolved. Don't get in a hurry here - you don't want cooked egg whites.
Transfer the egg whites to the bowl of a stand mixer fitted with the whisk attachment. Beat on medium-high (7 on a KitchenAid Mixer) until stiff peaks form and the mixture has cooled to room temperature, about 8-10 minutes. Reduce the speed to medium (5 on a KitchenAid Mixer) and add the butter 2 tablespoons at a time. Add more after each addition has become smooth and fully incorporated. The mixture may start to look soupy and curdled but continue to beat on medium-high speed until it is thick and smooth again, about 3-5 minutes.
Add 3 tablespoons of lime juice and mix on low until incorporated. Taste the frosting to ensure it is sweet enough and the lime flavor is dominate. If the mixture is not the right consistency, add 1 more tablespoon of lime juice. Mine became thick and almost butter like so I added confectioners' sugar, 1 tablespoon at a time, until it was smooth and creamy and had the right consistency.
Frost cupcakes using a piping bag and the desired tip to decorate.
Garnish with lime zest and lime slices if desired. The buttercream may be kept at room temperature or transfer to an airtight container and refrigerate up to 3 days. The frosting may also be frozen for up to 1 month. Before using bring the frosting to room temperature and beat on low speed with a mixer to achieve the proper consistency.
(cake slightly adapted from Cook's Country and the buttercream was adapted from Annie's Eats)
Have you ever tried Swiss Buttercream? What are your thoughts on the taste and consistency? I was pleasantly surprised at the light texture and less sweet taste and it was fun to make. My cake and icing skills need some work, so this was a good trial for me. Success!
Happy Monday friends! Thanks so much for stopping by.