Four years ago, when my eldest son turned nine, he declared that he was getting too big for the cupcakes I made every year on his birthday. He wanted a big cake.
Gasp. Cupcakes were safe. Cupcakes I could do. This was the day the cupcakes died.
It was early on in my food writing days and I, admittedly, had very little experience decorating bigger cakes. When I asked him what kind of cake he wanted, he announced it would be a lime cake and that it would be green, his favorite color. With fear and trepidation, I set out to make his birthday wishes come true and developed a recipe for a key lime cake from scratch. The recipe ended up being a favorite on the blog and one that I’m very proud of because it represents so many things – fears and insecurities being overcome, my son growing older, and food traditions being made. Ever since then, all three of my children have requested big cakes for their birthdays and cupcakes became a thing of birthdays past.
This week, as my son reached his thirteenth birthday, I revisited that first key lime cake recipe that made me the confident cake-baking mom I am today. I gave the recipe a springy, bright revamp just in time for Easter, transforming it into a lemon lime cake with citrus curd filling and cream cheese frosting. These two tangy, moist buttermilk layers with tart lemony curd in between were emphatically declared “awesome” by the new teenager in the house.
Lemon Lime Cake with Citrus Curd & Cream Cheese Frosting
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Tangy, citrus buttermilk layer cakes filled with tart citrus curd and finished with a citrus-scented cream cheese frosting.
For Cake:
1-3/4 cups flour (cake flour recommended)
1/2 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
1/2 cup butter, lightly softened
1-1/4 cups sugar
2 eggs
2 tablespoons freshly squeezed lemon juice
2 tablespoons freshly squeezed lime juice
2 teaspoons lemon zest
2 teaspoons lime zest
3/4 cup buttermilk
For Frosting:
1/2 cup butter, lightly softened
8 ounces cream cheese, lightly softened
2-1/2 cups powdered sugar
2 teaspoons lemon zest
2 teaspoons lime zest
1/2 teaspoon orange zest
For Citrus Curd:
Yields: About 1 cup of curd
3 eggs
3/4 cup sugar
2 tablespoons lemon juice
2 tablespoons lime juice
1 teaspoon lemon zest
1 teaspoon lime zest
4 tablespoons butter
Preheat oven to 350. Grease and flour two 8-inch round cake pans.
In a mixing bowl, stir together the cake flour, baking powder, baking soda, and salt. Set aside.
Using a stand-mixer fitted with the paddle attachment, beat the butter on low. Add the sugar and increase the speed to medium. Beat until fluffy, 3-4 minutes. Add one egg at a time, beating well after each addition. Add the citrus juices and zest, beating together until combined (the mixture will appear somewhat curdled at this point).
Add the flour mixture in three additions, alternating with the buttermilk, beginning and ending with the flour, scraping down the bowl as necessary. Mix on low until just combined.
Divide batter evenly between the two prepared cake pans and spread flat with an offset spatula.
Bake 25-28 minutes. Cool completely and fill with citrus curd (recipe below) and frost with cream cheese icing.
For Frosting:
In the bowl of a stand-mixer fitted with the paddle attachment, cream the butter until fluffy. Gradually add the powdered sugar on a low speed, increasing speed after the powdered sugar is incorporated. Add the citrus zests and beat to combine. For stiffer frosting, add another 1/4-1/2 cup powdered sugar as desired.
For Curd:
In a saucepan, whisk together the eggs and sugar until well combined. Whisk in the citrus juices and zest. Turn the heat on to medium-low and stir the mixture briskly and constantly until warmed through. Add the butter a little at a time until it melts into the mixture and becomes smooth. Continue cooking and stirring until the curd begins to thicken and coat the spoon. Refrigerate the curd in an airtight container until ready to use as filling for citrus cake with cream cheese frosting. Any leftover curd can be kept in the refrigerator for up to a week and used on biscuits or scones.
Decorator’s note: I piped a thick circle of the cream cheese frosting around the top perimeter of the bottom cake layer before spreading the citrus curd onto the cake. This helped prevent the curd from oozing out of the center of the cake when I frosted it.