Kumquat Layer Cake

I love SAYING “kumquats” (because it’s a funny word), EATING kumquats (because you get to pop them in your mouth whole) and BAKING with kumquats (because they have a bitter sweet citrus flavor).

Kumquat Cake from LibbieSummers.com

Kumquat Layer Cake
makes one 4-layer cake
(for the cake in the photo, I doubled the recipe and baked one 10-inch cake/cut into three layers, one 8-inch cake/cut into two layers, one 6-inch cake/cut into two layers…with frosting in between all layers)

2-1/4 cups all-purpose flour
2-1/2 teaspoon baking powder
1 teaspoon salt
1/3 cup butter
1/3 cup vegetable shortening
1 tablespoon grated kumquat zest (about 6 kumquats), save for juicing
1-1/2 cups vanilla sugar
3 large eggs, room temperature
1 cup fresh orange juice plus any juice from the zested kumquats  (from about 3 large or 4 medium oranges)
Kumquat Buttercream Frosting (recipe to follow)
Tons of sliced kumquats and a few fresh kumquats for garnish

Heat the oven to 350°F. Line 2 8-inch round cake pans and 2 6-inch round baking pans with parchment paper and spray with non-stick baking spray. Set aside.

In a medium mixing bowl, sift together the flour, baking powder, and salt.

In the bowl of a standing mixer fitted with the paddle attachment and on medium speed, cream together the butter, shortening, and zest. Gradually add the sugar, creaming until the mixture is light and fluffy, scraping down the sides of the bowl as necessary. Add the eggs, one at a time, mixing well between additions and scraping down the sides.

Add the sifted dry ingredients alternately with the orange juice to the creamed mixture, beating well on low speed after each addition. Pour equal amounts of the batter into the four prepared cake pans. Tap the pans on the counter before putting them in the oven to remove any air bubbles and to even the batter. Bake until a toothpick inserted in the middle comes out clean. Keep a close eye on them, because the different size cakes will bake at different times –anywhere from 16 to 28 minutes. Cool the cake layers in the pans for 10 min. and then loosen the layers by running a knife between the cake and the edge of the pan. Remove the layers from the pans and put them on a rack to continue cooling. Frost when cool with Orange Buttercream frosting and decorate with sliced kumquats (see close ups of the decorating process below).

Orange Buttercream Frosting
makes 5 cups 

2 cups (4 sticks) butter, at room temperature 6 to 8 cups confectioners’ sugar, sifted
1⁄2 teaspoon salt
1 teaspoon vanilla paste
1 teaspoon orange extract
4 to 8 tablespoons evaporated milk
orange food coloring

In the bowl of a standing mixer fitted with the paddle attachment, beat the butter on medium speed until creamy. Reduce the speed to low and gradually add 6 cups of the confectioners’ sugar. Increase the speed to medium and add the salt, vanilla paste, orange extract and 4 tablespoons of the evaporated milk. Beat for 2 minutes. If the frosting is too thin at this point, add more of the confectioners’ sugar, 1⁄2 cup at a time, and beat for 1 minute, until fully incorporated. If the frosting is too thick, add more of the evaporated milk, 1 tablespoon at a time, and beat for 30 seconds or until just combined. Divide the frosting into 2 bowls (3 bowls is you doubled the cake recipe and did a 10-inch cake too like I did). Using the orange food coloring tint the frosting into two shades of orange/medium orange/brighter orange (do a really pale orange if you baked the 10-inch cake too). Refrigerate the frosting for 20 minutes before using. Frosting can be made ahead and stored in the refrigerator for up to 1 week.

To Decorate:
I always start with a little inspirational sketch…some more crude than others.
I thought one layer of kumquat slices around the sides of the bottom layer of the cake, two layers of slices around the sides of the middle layer and covering the sides of the top layer would be beautiful. On the top, I thought a pile of kumquats and leaves would be a great way to keep a little bit of an organic feel and show off the beauty of the fruit.

Kumquat Cake Sketch from LibbieSummers.com

Frost the cake layers using the coordinating frosting color for each diameter of cake. Make sure to do a crumb coat before the final coat. For a fun tutorial video on how to frost a layer cake, click HERE.

Then, I sliced a TON of kumquats. This takes a lot more than I thought (about 30). Make sure your knife is sharp because you’ll be cutting through some seeds. Luckily, I had a brand new handmade knife from Sam Densmore that my niece, Corie, had so generously given me for Christmas. You have to check out Sam’s knives. They are works of art AND I loved the way it cut and felt in my hand. I’m a bit of a knife snob and I couldn’t be more pleased with this knife…but more on that later.

It’s important to note that your frosted cake layers should be pulled out of the refrigerator about 10 minutes before adding the kumquat slices or they won’t stick. I worked from the bottom up following my sketch.


So stinkin’ cute right!! Good enough to insta. A celebration of the citrus season.
Kumquat Layer Cake from LibbieSummers.com