These lime cupcakes are among my absolute favorite things to make. They are somewhat time consuming, but the end result is completely worth it.
If it’s possible for something to be rich, and at the same time light and refreshing, these cupcakes are just that. The flavor is bright and tangy, and the texture of the frosting is airy, with a rich buttery mouth-feel. It’s all very contradictory, but pleasing at the same time.
If you’ve never made swiss meringue buttercream, I urge you to try it. It is my favorite frosting these days (aside from a quick and easy cream-cheese frosting), despite the fact that it does take a little time and effort.
Preheat the oven to 350F and line a 12-cup muffin pan with paper liners
Zest 5 limes and reserve zest
To make lime simple syrup:
Juice the limes – should be about a cup of lime juice
Combine juice with 1 cup of sugar in small saucepan and simmer over low heat until sugar dissolves. Reserve this syrup for use in frosting and for brushing tops of cupcakes.
2 1/2 cups flour
1 tablespoon baking powder
1/4 teaspoon salt
Beat in a large bowl until thick and light in color:
8 large egg yolks
1 teaspoon vanilla
zest of 5 limes
1 teaspoon fresh lime juice
Cream together in a separate bowl:
1 1/2 sticks of butter
1 1/4 cups sugar
Beat the yolk mixture into butter mixture. On low spead, add the flour mixture in 3 parts, alternating with:
3/4 cup milk
in two parts, beating until smooth.
Divide the batter among the 12 muffin cups and bake for 20-30 minutes on a rack in the center of your preheated oven. Allow to cool on a rack. You may have to trim the cupcake tops – mine rose and spread significantly.
For swiss meringue buttercream:
In bowl of electric mixer, combine:
4 egg whites
3/4 cup sugar
2 tablespoons water
1/4 teaspoon cream of tartar
Place bowl over a pan of simmering water, creating a double boiler. Insert a candy thermometer and stir mixture constantly until it reaches 160F. Affix bowl to mixer fitted with whisk attachment and whisk on high speed until stiff peaks have formed. Add 1 teaspoon vanilla extract.
In a seperate bowl, beat:
3 sticks softened butter
until light and fluffy. Beat a large dollop of the meringue mixture into the butter mixture until well combined. Continue to beat in about half the meringue in large dollops. Scrape the remaining meringue into the mixture and beat until smooth and fluffy. Beat in 1/2 the reserved lime simple syrup.
Brush tops of trimmed cupcakes with remaining reserved lime syrup.
Place frosting in a pastry or ziploc bag fitted with a 1/2 inch star tip and pipe frosting onto tops of cupcakes.
If not serving immediately, keep refrigerated. To serve, remove from fridge and allow to come to room temperature so frosting can soften.