Lemon-Mascarpone Layer Cake with Edible Flowers

Over Christmas break I stopped by to see my old high school friend Claire. As I was leaving, she offered me lemons from her overflowing tree. My first instinct was to decline, since I was staying with my parents and had no interest in shlepping random lemons back home with me in my already-overstuffed car. Plus, I had chocolate buche de noel on the brain, not lemons.


However, once I saw that her tree was full of Meyer lemons, I did a ten-point vault over her head and raced to the tree, yelling at her to dust herself off and bring the biggest cardboard box she could find. As a result of my wanton selfishness, I ended up with a generous supply of this awesome fruit.

Most folks are probably familiar with Meyer lemons, but if you're not, here's a handy visual comparison:

The usual lemon suspect, the Eureka lemon, is on the left. It's a light yellow color, with a thick rind and a sour citrus flavor. The Meyer lemon is on the right. They're usually rounder than the traditional lemon, with a yellowy-orange color, a thin rind, and a perfumey, almost floral fragrance. Wikipedia tells me it's thought to be a cross between a lemon and an orange, which makes sense, since it's juice is sweeter and more complex than the usual super-tart lemon juice.

But enough lemonology. The question is, what did I do with them? Well, Claire handed me Meyer lemons, and I made Lemon Mascarpone Layer Cake:
Two of my good friends had birthdays this month, so a group of us got together for a girl's night out to celebrate them. We could have had desserts at the restaurant, but there's something special and personal about a homemade birthday cake, and I wanted them to feel the love, so I arranged with the restaurant to bring our own cake.
The cake I chose was from The Art and Soul of Baking, a beautiful cookbook given to me by another friend. A basic genoise cake is brushed with lemon syrup and layered with lemon curd and a lemon-mascarpone-whipped cream mixture. The result is a light, pillowy cake that is almost like a trifle, it's so creamy and moist. If I had any criticism it's that the lemon flavor and lemon curd layers could have been heavier, so in the instructions below I've changed the quantities to suit my tastes.
But what really makes this cake special are the flower decorations, and that part couldn't be easier. Here, I've written all the steps out for you:

1. Go to Whole Foods or another upscale grocery store
2. Buy organic "Edible Flowers"--they're usually in the prepackaged herb section
3. Put edible flowers on cake
4. Bask in warm glow of compliments and adoration

Edible flowers are stunningly beautiful, and require absolutely no work or skill to decorate with. I really can't recommend them enough. In answer to the inevitable question "But what do they taste like?" the answer is pretty much...nothing. They have a slight green taste, sort of like a lettuce leaf, but in general it's like a whole mouthful of nuthin'. Because the cake was heavily loaded with flowers, we ate some but ended up leaving some on our plates. I think of them like fondant--a beautiful decorating touch but not necessarily meant to be consumed with the cake.

And here's the secret to getting a birthday plaque to stay at an angle: lots and lots and lots of whipped cream! It's a very lucky birthday girl indeed who got that piece of cake.

Read on for the full recipe, and don't be intimidated by all the steps! It can easily be modified by using your favorite sponge (or box) cake, store-bought lemon curd, and simple whipped cream instead of the whipped cream-mascarpone mix.



Lemon Mascarpone Layer Cake
adapted from The Art and Soul of Baking by Cindy Mushet

For the cake
[you can subsitute any light sponge cake you like in this recipe]
6 large eggs, separated
6 oz (14 tbsp) sugar, divided use
6 oz (1.75 cups) sifted cake flour
Zest of one lemon

Preheat the oven to 375 F. Line two 9" cake pans with parchment paper, but do not grease them in any way.

Whip the egg yolks with half of the sugar (3 oz, or 7 tbsp) in the bowl of a large stand mixer on high speed for 5 minutes, until they are very thick and light in color. Transfer the yolks to a separate bowl and wash the mixing bowl and whisk very well.

Whip the egg whites in the cleaned mixing bowl until soft peaks form. Gradually add the remaining 3 oz/7 tbsp sugar a spoonful at a time, while mixing on high speed, until the egg whites hold firm peaks.

Fold one-third of the egg whites into the yolks with a spatula, then sift half of the cake flour on top and gently fold it in. Fold a second third of the egg whites into the yolks, sift the remaining cake flour on top, then fold that in. Finally, add the last of the egg whites, and when they're almost incorporated, add the lemon zest and fold until everything is mixed together.

Divide the batter between the two pans and bake for 18-22 minutes, until the tops are golden, firm, and a toothpick inserted in the center comes out clean. Transfer the cakes to a rack to cool completely.

For the lemon syrup
1/2 cup granulated sugar
1/2 cup water
1/4 cup fresh-squeezed lemon juice

Heat the sugar and water in a small saucepan over medium-high heat, stirring occasionally, until the sugar dissolves and the liquid is clear. Remove from the heat and stir in the lemon juice. Allow to cool completely before use.


For the lemon curd
5 large eggs
5 egg yolks
1.5 cups sugar
1 cup + 2 tbsp fresh lemon juice
9 tbsp (4.5 oz) cold unsalted butter, cubed

Fill the bottom of a double-boiler with 2 inches of water and bring it to a simmer.

Place the eggs, yolks, and sugar in the top of the double boiler (off the heat) and whisk until blended. Add the lemon juice and mix well. j

Place the egg mixture over the simmering water and cook, whisking constantly, until the curd reaches 180 F on a candy thermometer. (If you don't have a thermometer, it should thicken enough to coat the back of a spoon.) Don't let the curd boil, or you'll have bits of scrambled egg in your curd.

Once cooked, strain the curd through a metal strainer into a bowl. Add the cold butter pieces to the curd, and whisk gently until the butter melts and the mixture is velvety-smooth. Press a layer of cling wrap on top of the curd and refrigerate it until it is cool, at least 3-4 hours or overnight.


For the mascarpone filling
2.5 cups (20 oz) heavy whipping cream
3 oz (7 tbsp) granulated sugar
1 lb mascarpone, I suggest making your own if you have time--it's much better and cheaper

Place the cream and sugar in the large bowl of a stand mixer and whisk until they form firm peaks, but do not over-beat or it will become grainy and curdled.

In a large bowl, combine the mascarpone and 1-1/2 cups of lemon curd, and stir until they're well-mixed. It should be the consistency of pudding. Gently fold the whipped cream into the mascarpone mixture, being careful not to overmix, or the mascarpone will look grainy and separated. If this happens, stir in a spoonful or two of heavy cream to smooth it out.


To assemble the cake

Unmold the cakes, and use a sharp serrated knife to cut each one in half, so you're left with four thin cake rounds. Place one round on a cake cardboard and brush it with a quarter of the lemon syrup.

Spoon about 1/3 cup of the mascarpone filling on top of the cake round, and use a spatula to spread it evenly around. Top the mascarpone with about 1/3 cup of lemon curd, and spread it in a thin layer.

Place another cake round on top of the first, and brush this one with an equal amount of lemon syrup. Repeat the layer of cake rounds, lemon syrup, mascarpone, and lemon curd until you have added the final cake round to the top of the cake. Brush the top with the remaining lemon syrup.

Spread the remaining mascarpone mixture along the top and sides of the cake. If you have lemon curd left over, you can pipe dots of lemon curd along the top of bottom border of the cake (or you can just save it to eat on toast and oatmeal!)

This cake is best made a few hours--or even a day or two--in advance, so the flavors and textures have a chance to meld.