Buttermilk Chiffon Cake with Key Lime Curd

I had an awful lot of buttermilk and egg whites left over from the Baseball and Princess parties we did recently. I wanted to find a way to use them up. I found this recipe, and adapted it a little to my understanding of the foaming method.

Looking in the store for inspiration, I saw that key limes were inexpensive. I love key limes, so I decided a key lime curd would be awesome as filling in the cake. I adapted this recipe for my curd.

The frosting is a vanilla lime Swiss butter cream. It is flavored with a little key lime zest, and some vanilla extract.

To garnish the cake, I candied some key lime slices in a simple syrup.

I really like this cake. This recipe is a keeper. The cake is not as fluffy as the chiffon cake I learned to make in school. It still has a very tender crumb, and there is definitely a bit of buttermilk tang to the flavor. It is a sturdier cake, and would hold up to more manipulation, if one was inclined to do something interesting with the construction.

The key lime curd is bright and acidic, and very intensely flavored. I added just a touch of green food coloring, to help with the visual cue that this is not lemon.,

I am very pleased with this cake. It is firm, but still moist and tender. I like the intensity of the curd. I think it's acidity helps cut the sweetness, and that plus the buttermilk helps give depths and complexities of flavor. The lightly flavored butter cream frosting complements, without overshadowing, the cake.

Recipes

Buttermilk Chiffon Cake

3 cups cake flour
1 tsp. baking soda
1/2 tsp. salt
1 cup shortening
1 1/2 + 1/2 cups sugar
1 cup buttermilk
1/2 tsp. almond extract
6 oz. by wt. egg whites
1 tsp. cream of tartar

Pre-heat oven to 350 F.

Grease and flour two nine inch round cake pans. Line bottoms with wax or parchment paper.

Sift together flour, baking soda, and salt. Set aside.

In the bowl of a stand mixer, cream together shortening and 1 1/2 cups sugar until light and fluffy. Add flour mixture in stages, alternating with buttermilk. Beat to combine thoroughly between each addition.

Beat egg whites until foamy. Add almond extract and cream of tartar. Whip to soft peaks, then slowly add 1/2 cup sugar. Whip to medium stiff peaks.

Fold 1/4 of egg whites into batter to lighten. Gently fold in remaining whites, until whites and batter are well combined, with no visible streaks of whites remaining.

Divide batter between cake pans.

Bake 25 - 30 minutes, or until cake is firm. Remove to rack to cool.

Key Lime Curd

1 cup sugar
4 eggs, beaten
1/2 cup fresh squeezed key lime juice
2 Tbsp. key lime zest
pinch kosher salt

Combine all ingredients in a small sauce pan over medium low heat. Cook, whisking constantly, until curd thickens, about ten minutes.

Strain curd. cover surface with plastic wrap to prevent a skin from forming. Chill in freezer for 20 minutes, then transfer to refrigerator to finish cooling.

Vanilla Lime Swiss Butter Cream Frosting

6 oz by wt. sugar
4 1/2 oz by wt. egg whites
1 Tbsp. + 2 tsp. water
1 lb. butter cut into 1/2 inch cubes
1 tsp. vanilla extract
zest of one key lime
 1/4 tsp. kosher salt

Heat sugar, egg whites, and water in a double boiler to 160 F, whisking continuously. Whip in a stand mixer five minutes, or until mixture decreases to room temperature. Add butter one chunk at a time, until all the butter is Incorporated. Add salt, vanilla, and lime zest. Whip until smooth and glossy.

Happy Eating!

Pastry Class: Chiffon Cake

We are now getting down to some serious business in my pastry class. We made a chiffon cake with lemon syrup, raspberry and whipped cream filling, and Swiss buttercream frosting. The chiffon cake was much more involved than the other things we have made.

The cake was used to illustrate the Foaming method. In this method, eggs are whipped to incorporate air, then added to the batter. The air bubbles in the egg foam provide leavening, resulting in a light and airy product.

There are several parts to this cake. There is the cake itself, the lemon syrup, the fillings, the frosting, and the decorations.

The cake is a vanilla chiffon cake. It begins with the Mix Method, where the dry ingredients are sifted together, the wet ingredients whisked together, then added to the dry. The change begins when egg whites are whipped with powdered sugar to a meringue, and added to the batter. This is a French meringue, where the eggs are uncooked in any way. Not an issue, as the cake will be baked at a sufficient temperature to kill any unwanted micro-organisms.

The syrup is a simple syrup of water, sugar, and lemon juice.

For the raspberry filling, we used a commercial filling. I suspect a raspberry jelly or jam would work just fine. We used a sweetened whipped cream as well for the filling.

The frosting is a Swiss buttercream. It involves making a Swiss meringue. In a Swiss meringue the egg whites are cooked with sugar and water over a double boiler until they reach a temperature of 160 degrees F. This ensures that micro-organisms are killed, so Swiss meringues can be used as decoration or other applications that do not require cooking.

Once the cake is baked and completely cooled, and everything else is made, the cake can be assembled. The cake is split horizontally into three equal layers. This is a very delicate cake, so when cutting, spreading, or frosting, care must be taken not to tear the cake. Once cut, a thin layer of raspberry filling is spread on the first layer. An approximately one quarter inch thick layer of whipped cream is placed on top of that. The second layer of cake is added next, and the same procedure is done, ending with placing the top layer on.

Next, a thin layer of frosting is applied to the the top and sides of the cake. This is called the crumb coat. It will lock in stray crumbs, and keep them out of the frosting. Refrigerate the cake for ten minutes. This will set the crumb coat hard. Apply an even coat of frosting.

For the outside of the cake, we coated it with toasted chopped almonds. We piped a shell on each piece, and added alternating a chocolate straw, and a triangle of chocolate with a cool transfer design. We didn't make either of the chocolate decorations, I think they were left over from Chef James chocolate class. They do add a particularly professional flare, though.

As always for the pastry class, all recipes are provided by Chef James Foran.

Recipes

Vanilla Chiffon Cake

dry ingredients
9 oz by wt. cake flour
7 oz by wt. sugar
1 Tbsp. baking powder
1/2 tsp. salt

wet ingredients
6 egg yolks
2/3 cup water
4 oz by vol. oil
1 Tbsp. vanilla paste

meringue
8 egg whites
3.5 oz by wt. sugar
1/2 tsp. cream of tartar

Sift together dry ingredients. In a separate bowl, whisk together wet ingredients. Add wet ingredients to dry all at once. Mix just until everything is Incorporated.

In a stand mixer with a whisk attachment, whip egg whites on high speed until frothy. Turn down to medium speed, and slowly add sugar and cream of tartar. Turn back to high, whip to medium, stiff peaks.

Fold one quarter of the meringue into the batter until just combined. Fold remaining meringue in gently, until no streaks of batter or meringue are visible.

Divide batter evenly between two ungreased nine inch cake pans lined with parchment paper. Bake in a 325 F oven for 30 minutes, or until cakes are golden and springy to the touch. Remove from oven, and cool on a rack.

Lemon Syrup

4 oz by vol. water
4 oz by wt. sugar
4 Tbsp. lemon juice

Bring water and sugar to a boil. Remove from heat, add lemon juice. Allow to cool.

Vanilla Chantilly

12 oz by vol. cream
.7 oz by wt. powdered sugar
1 1/2 tsp. vanilla extract
pinch salt

Whip all ingredients together to medium stiff peaks.

Swiss Buttercream

6 oz by wt. sugar
4 1/2 oz by wt. egg whites
1 Tbsp. + 2 tsp. water
1 lb. butter cut into 1/2 inch cubes
1 tsp. vanilla extract
1/4 tsp. kosher salt

Heat sugar, egg whites, and water in a double boiler to 160 F, whisking continuously. Whip in a stand mixer five minutes, or until mixture decreases to room temperature. Add butter one chunk at a time, until all the butter is Incorporated. Add salt and vanilla. Whip until smooth and glossy.

Happy Eating!