I love filled cupcakes. I feel like they are this awesome surprise tucked inside this otherwise innocuous pastry. I mean, from the outside, totally a plain vanilla cupcake, jazzed up with some sprinkles. Take a bite and POW a mouthful of cool, tangy lime curd!
Since we have so many parts, we’re going to keep the cake a simple vanilla cupcake. I like to use regular cake mix but your favorite vanilla cake recipe will do.
Swiss Meringue Buttercream
These cupcakes are piled high with a different kind of buttercream then we’ve used before. My go-to is typically American buttercream because it comes together quickly and easily, but sometimes the sweetness is a little overpowering. Enter Swiss meringue buttercream.
Swiss meringue buttercream is a little more fussy than American buttercream, but the smooth silky texture really lets the lime flavor shine. It’s worth a little bit of extra hassle (a.k.a cooking). It’s made by cooking a simple sugar syrup and pouring it over beaten eggs whites. The best part (besides the flavor, of course) is no powdered sugar poof all over the kitchen!
Lime Curd adapted from The Cake Bible
- 4 egg yolks
- 1/2 cup sugar
- 4 tablespoons butter room temperature
- 1 teaspoon vanilla
- 3 ounces lime juicezest from limes
- Stir together egg yolks and sugar in a medium sized heavy saucepan. Pour in lime juice.
- Stirring constantly, cook over medium heat until mixture thickens enough to coat the back of a spoon. Do not allow mixture to boil. It will curdle your eggs
- After the mixture thickens, remove from heat. Stir in butter and vanilla.
- Send mixture through a fine mesh strainer and stir in lime zest.
- The lime curd will be yellow. This is totally fine, but if it weirds your sister out to have yellow lime curd like it does mine, then you can add a drop or two of green food coloring.
- Cover with plastic wrap right down on the curd to prevent a skin. Refrigerate for at least 1 hour.
Lime Buttercream adapted from Sky High Irresistible Triple Layer Cakes
- 4 egg whites
- 1 cup sugar
- 1/3 cup lime juice 3-4 limes
- 3 sticks butter at room temperature
- zest from 2 limes
- In a medium sized heavy saucepan, heat up the sugar and lime juice and stir to dissolve the sugar.
- Bring to a boil and cook until the syrup reaches 238 degrees Fahrenheit (soft ball stage).
- Set up stand mixer with the egg whites and lime zest in the bowl and the whip attachment. Turn the mixer on low and beat the eggs until they are frothy.
- Slowly add the syrup.
- Continue beating on medium high speed until the egg whites have whipped up and the bowl is cool to the touch.
- Slowly add the butter, one tablespoon at a time.
- Continue beating, the mixture will look lumpy and broken for quite awhile. Keep beating, eventually it will become a smooth buttercream.