Lemon Mascarpone Cream Cake

Happy Monday, everyone!

So we're following up last week's easy cookie theme with something a little more fussy. Something that would get my apron dirty.

Today's cake is divine. Frosted with whipping cream, stabilized with mascarpone cheese and flavored with lemon curd. It's light, creamy and not too sweet. The cake is moist and dense, yet fluffy with a delicate crumb. Layered with a little lemon curd and the mascarpone frosting, it's easily one of my favorites.

The cake is a high ratio cake, which is a little different than your average cake; it doesn't use the more commonplace creaming butter and sugar method. Instead you blend all the dry ingredients with the butter and a bit of liquid, then add the wet ingredients. This method requires a stand mixer, as beating by hand would be too slow and it would likely be hard on hand beaters. Precision is very important in this recipe, so be sure to use the correct ingredients and follow the exact mixing times and speeds when making this cake.

High Ratio Yellow Butter Cake
from the CIA's Baking at Home
yields two 8" cakes
3 1/2 cups cake flour
2 cups sugar
1 tablespoon baking powder
1/2 teaspoon salt
1 cup (2 sticks) unsalted butter, diced, at room temperature
1 cup whole milk, divided
4 large eggs
2 large egg whites (reserve the yolks for the curd)
2 teaspoons vanilla extract

Tools:
parchment for the pans
Professional 3-inch high sided, 8" round pans. (The cake will rise well beyond the sides of short cake pans.)
Non-stick cooking spray

Preheat your oven to 350°F. Lightly coat your pans with cooking spray and line the bottoms with circles of parchment.

Cut your butter into small cubes while it still has a slight chill (it's easier to cut), and then allow to stand at room temperature  until it softens. It won't take long when the butter is diced.

In a bowl, lightly beat the eggs, egg whites, vanilla extract and half of the milk. Mix until more or less homogeneous and set aside.

In the bowl of your stand mixer, sift together the cake flour*, sugar, baking powder and salt.  (*Tip for measuring cake flour: Don't scoop.  Spoon the cake flour into your measuring cup, directly from the package, and then level your cup with the back of a knife.)

I often whisk together my dry ingredients after sifting, to ensure salt and leavening is evenly distributed

Fit the bowl into your stand mixer and equip the whisk attachment. Add the butter and remaining half cup of whole milk. Beat this mixture on medium speed until smooth (about 4 minutes), scraping down the bowl with a spatula as needed.

The mixture will start out a little rough and then turn pasty and thick.  Once beaten, add a third of the egg-milk mixture and mix for two minutes on medium speed. Add another third and beat on medium speed for two minutes, you'll notice the mixture beginning to increase in volume. Add the remaining third of the milk-egg mixture and beat on medium speed for two minutes.

Finished cake batter. Very fluffy.

Divide the batter between your two pans (it will be roughly 670 grams per pan).

Level the batter with an offset spatula and bake for 35-40 minutes. They will be done when the cake springs back slightly when lightly touched in the center. If you touch the cake and it feels under-baked, feel free to give it another 5 minutes in the oven to set. 

Remove from the oven and allow to cool completely in the pans on a wire wrack.  The cake should pull away from the sides as it cools. If it doesn't, slip a knife around the side to release. Once cool, remove the cake from the pan and peel off the layer of parchment.

Trim the tops of the cake with a sharp serrated knife.

The cake should have a nice even crumb, with no tunnels. Tunnels in cake are often a sign of issues with mixing.

While you're waiting for those beautiful cakes to cool, work on the lemon curd and mascarpone frosting.

Lemon Curd
adapted from Luscious Lemon Desserts
1/2 cup unsalted butter
1/2 cup lemon juice
zest of one large lemon
3/4 cup granulated sugar
1 teaspoon cornstarch
pinch of salt
6 large egg yolks

Melt the butter in a medium sauce pan over medium-low heat.  Remove from heat and add the lemon juice and zest.

Mix together the sugar, salt and cornstarch and add it to the pan.  Whisk in the egg yolks until smooth and return to heat. Cook over medium-low heat for roughly 10 minutes until the mixture has thickened and coats the back of a spoon. Do not allow the mixture to boil.

Once thickened, strain the mixture though a fine mesh strainer into a large bowl. Allow to chill in the refrigerator completely before using.

Lemon Mascarpone Cream Frosting
adapted from The Art and Soul of Baking
yields enough to frost a 4 layer cake or generously frost a 2 layer cake
1 pound mascarpone cheese
5 ounces (2/3c) lemon curd
20 ounces (2 1/2c) heavy cream
3 ounces (7Tb) sugar

Beat the sugar and cream to soft peaks in your mixer.

Combine the mascarpone and lemon curd in a separate bowl and mix.

Add the cream to the mascarpone mixture. Gently fold to combine. If the mixture is overworked it can separate or look grainy. To fix this add several tablespoons of heavy cream and mix with the spatula until smooth again.  If you're baking karma is good, you can dump the mascarpone mixture into the cream and briefly beat with your stand mixer on medium low speed.

Left: Mascarpone curd mixture. Right: Finished frosting.

Now you're ready to assemble the cake.

Drop a dollop of the mascarpone frosting onto the cake and smooth to seal the top. Fill a piping bag with a large round opening with frosting and then pipe a boarder around the top of the cake. This will contain your lemon curd. Fill the center of the cake with roughly 1/3 cup of lemon curd. Then cover with a layer of frosting. The easiest way to cover slippery lemon curd with an even layer frosting is to use that same piping bag you made the boarder with. starting in the center of the lemon curd, pipe a tight spiral of frosting. Coil it tightly, around and around until you've reached the edge of the cake.

Gently place the second layer of cake on top.

To crumb coat the cake: Apply a thin layer of frosting over the entire cake and chill for 30 minutes. Then apply a thick layer of frosting over the cake. Using your cake tool of choice (I get by with a small offset and large flat spatula for frosting cakes), smooth the frosting over the cake.

If you're nervous about making a smooth sided cake, a cake comb can make the process a little easier.

Now you can decorate.

Now unfortunately for me, my 2 year old daughter thinks fishing around in my cake decorating tips is the best thing ever. She seems to have removed my small and medium star tips and I've had to resort to a star tip that is better suited to cupcakes than cakes, so bear with me (decorating-wise).

Pipe a boarder on the top of your cake and then cover the top with some of the remaining lemon curd.

Enjoy responsibly.

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