These are really tasty and super refreshing, and actually look kind of fancy too. They’re a little complicated because you have to make three separate sections – the cupcake itself, the filling and then the icing on top. But totally worth it.
Ingredients
Lime Filling
· ½ cup sugar
· 1 egg
· 1 (additional) egg yolk
· ¼ cup fresh lime juice (from about 4 limes?)
· 2 t cornstarch
· 4 T butter, softened to room temperature
· 1 t lime zest (probably just 1 lime)
· 1/8 t salt
Cupcakes
· 12 T butter, softened to room temperature
· 1 ¼ cup flour
· ½ t baking soda
· ½ t baking powder
· ½ t salt
· ¾ cup sugar
· 2 eggs, brought to room temperature
· 1 ½ t vanilla
· 1 t lime zest
· 2 T fresh lime juice (1 lime probably)
· 1/3 cup buttermilk
Frosting
· 1 stick (8 T) butter, softened to room temperature
· 3 ¼ cup powdered sugar
· ¼ cup sour cream
· 1 T lime juice
· 1/8 t salt
· Lime zest (about one T), for decoration
In a small saucepan, pour the sugar, egg, egg yolk, lime juice and corn starch. Cook over a medium to low heat (just below boiling) , whisking constantly, for about 8 minutes until the mixture thickens. Remove it from the hear and whisk in the butter until it’s completely melted and the mixture is smooth. Finally, whisk in the lime zest and the salt. Next, on to the cupcakes themselves. In a small bowl whisk together the flour, baking powder, baking soda and salt and set aside. In a large bowl put the butter and sugar and mix that with a hand mixer until it’s smooth, probably 3-4 minutes. Add in the eggs, vanilla, lime zest and lime juice and mix that until everything is well combined. Pour half of your flour mixture into the larger bowl and mix until well combined. Then take half the buttermilk, mix that in until its well combined. Then repeat that – first the remaining flour mix then the remaining buttermilk. Place muffin cups into a muffin tin and fill each about three quarters full. You should have enough batter for about 15 total cupcakes. Bake the cupcakes at 350 for about 20 minutes, until they start to get a little brown at the edges and a toothpick stuck in the center comes out clean. Move the cupcakes to a wire rack and let them cool completely. Once the cupcakes are cool you can fill them with the filling you’ve already made. Put the filling into a pastry bag equipped with a tip – it doesn’t have to be a fancy one and it doesn’t really matter which one you use as long as its hard metal or plastic. I’ve often recommended using plastic bags as pastry bags and usually that works but in this case you need the tip to be firm because you’re going to put the tip all the way into the center of the cupcake and squeeze the bag. You’ll know you’ve put enough in when you see the edges of the cupcake start to swell out. After you’ve filled the cupcakes you can make the frosting. Put the butter and powdered sugar into a bowl and beat them together until their fluffy, about 5 minutes. Then, add the sour cream, lime juice and salt and beat for another couple minutes. You can either frost the cupcakes by piping the frosting on or do what I did and just use a knife. It’s probably not as pretty but anyone who’s read any of my desserts knows that’s not my top priority. Sprinkle some lime zest on top of each cupcake (see? Instant fancy!) and serve. These cupcakes are super moist, tart and sweet and are absolutely delicious. They take a little time because you have to make three parts, but they are SO worth it.Directions
First we’ll make the filling.
Place the whole saucepan into a larger bowl half filled with ice, and continue to whisk until the lime curd you’ve made is completely cool.
Cover the saucepan and put it in the fridge until we’re ready to fill the cupcakes.