California Winter Cake—White Chocolate + Grapefruit

California was a treat, my dudes. Comprised of the usual spate of woodworking, welding, and face-stuffing with tacos, it was a completely undeserved and welcome respite from Baltimore’s too-long winter. Obviously there were gobs of citrus too, and after a long while spent pining for the lemon cream that Yossy loves, I went grapefruit on it and figured it was cake-worthy. The results totally ruled, and little needs to be said about this excellent thing, except perhaps that it was born of a winter vacation to a summery place—and it shows. A standard white cake recipe from the best baking dudes, sandwiched with a perfectly bitter, citrusy cream, dressed in a white chocolate ermine frosting that might supersede all previous frosting allegiances, and topped with my favorite roasted white chocolate garnish. Make it if you’re seeking celebration or a big fat slice of end-of-winter Hell-Yes. 

For cake layers

Cake and frosting adapted from Baked: New Frontiers in Baking

Yield: Three 7- or 8-inch cake layers

2 1/2 cups of cake flour

3/4 cup all-purpose flour

1 tablespoon baking powder

1 teaspoon baking soda

3/4 teaspoon salt

1/2 cup (8 tablespoons) unsalted butter, softened

1/2 cup vegetable shortening

1 3/4 cups sugar

1 tablespoon pure vanilla extract

1 large egg

1 1/2 cups ice cold water

3 large egg whites, at room temperature

1/4 teaspoon cream of tartar

1.  Preheat the over the 325 degrees F. Butter and flour three 7- or 8-inch round cake pans with removable bottoms. Sift the flours, baking powder, baking soda, and salt together in a large bowl. Set aside.

2.  In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and shortening on medium speed until creamy, three to four minutes. Add the sugar, and beat on medium speed until fluffy, about three minutes. Scrape down the bowl, add the vanilla and whole egg, and beat until just combined. Turn the mixer to low. Add the flour mixture, alternating with the ice water, in three separate additions, beginning and ending with the flour mixture. Scrape down the bowl, then mix on low speed for a few more seconds.

3.  In a medium bowl, whisk the egg whites and cream of tartar until soft peaks form. Do not overbeat. Gently fold the egg whites into the batter. Divide the batter among the prepared pans and smooth the tops. Bake for 40 to 45 minutes, rotating the pans halfway through, until a toothpick inserted in the center of the cake comes out clean. Transfer the cakes to a wire rack and let cool for ten minutes, then carefully remove cakes from pans and let cool completely. Remove the parchment.

4.  A tip for assembly: Have frosting and filling prepared when ready to assemble cake. The most important part of the whole she-bang? Pipe a generous, tall border of frosting around the edges of each layer, and fill the well with about a half-cup of grapefruit cream. The border will keep the cream from sandwiching out between the layers.

For white chocolate ermine frosting

6 ounces white chocolate, coarsely chopped

1 1/2 cups sugar

1/3 cup all-purpose flour

1 1/2 cups milk

1/3 cup heavy cream

1 1/2 cups (3 sticks) unsalted butter, soft but cool, cut into small pieces

1 teaspoon pure vanilla extract

1.  Using either a double boiler or a microwave, melt the white chocolate and set it aside to cool.

2.  In a medium heavy-bottom saucepan, whisk the sugar and flour together. Add the milk and cream to cook over high heat, whisking constantly, until the mixture comes to a boil. Allow to boil for one minute, whisking quickly the whole time and being very careful not to scorch; all told this takes about ten minutes.

3.  Transfer the mixture to the bowl of an electric mixer fitted with the paddle attachment. Beat on high speed until cool; the goal is to have the mixture be cool enough to emulsify rather than melt the butter. Reduce the speed to medium and add the butter; mix until thoroughly incorporated. Increase the speed to medium-high and beat until the frosting is light and fluffy.

Add the vanilla and white chocolate and continue mixing until combined; it should thicken immediately. Use right away or, if frosting is too thin, thicken it up in the fridge for 20 to 30 minutes until it reaches desired consistency.

For the grapefruit cream filling

Adapted from Tartine Bakery, via Food52

Yield: 2 ½ cups, about twice what you'll need for a cake

1 cup grapefruit juice, reduced to ½ cup  

2 tablespoons lemon juice

3 large eggs

1 large egg yolk

6 tablespoons granulated sugar

Pinch salt

12 tablespoons unsalted butter, cut into tablespoon pieces

1. Pour water to a depth of about 2 inches into a saucepan, place over medium heat, and bring to a simmer. Combine the juice, whole eggs, yolk, sugar, and salt in a stainless steel bowl that will rest securely in the rim of a saucepan over, not touching, the water. (Never let the egg yolks and sugar sit together for more than a moment without stirring; the sugar will cure the yolks and turn them granular.)

2.  Place the bowl over the saucepan and continue to whisk until the mixture becomes very thick and registers 180 degrees F on a thermometer—ten to 12 minutes. Remove the bowl from over the water and let cool to 140 degrees F, stirring from time to time to release the heat.

3.  When the base is cool, pour it into a countertop blender. With the blender running, add the butter one tablespoon at a time, blending after each addition until incorporated before adding the next piece. The cream will be pale yellow and thick. It can be used immediately, but I had better results letting it thicken up in the fridge more. The cream will keep covered in the fridge for five days; do not store in a metal bowl.

Grapefruit-Ginger Meringue Tart

As a Californian, I am compelled by my upbringing to love citrus (and avocados and Mexican food). Growing up in San Diego, I was lucky enough to be able to walk out the side door and into the orchard where the juiciest oranges, lemons, tangerines, and, randomly, grapefruits were ripe for the picking. Avocados too. The grapefruits hung from the neighbor’s tree, but as a kid I had no boundaries, and as an adult, those habits were hard to break (as if I even tried). I didn’t quite appreciate the extent of our bounty until I moved away, but even then my parents would pack up boxes of orchard oranges and flat-rate ship them to me, not because I didn’t have access to citrus, but mostly because their trees were actually bending under the weight of too much fruit and oranges were rotting on the ground. How totally unfortunate for them.

And then my parents moved away too. Now they live in a house with a smaller yard in central San Diego, with a little Charlie Brown orange tree out back that my sister gifted, and it’s been about a year since I’ve been up to my ears in backyard citrus. The dearth had been pretty much fine with me until Lottie + Doof retweeted a photo of an incredible-looking blood orange pie from Nightwood in Chicago, and BAM, love of citrus reignited. After several failed orangey desserts and a lot of grapefruit brulee, I read 101Cookbooks’s account of her many citrus curds (ugh, time to move home) and of course thought of lemon meringue.

I made this tart first for Pi(e) Day two weeks ago and then remade it more carefully last week when my pal Tory lent me her KitchenAid mixer in exchange for her ice cream maker, which I am also long-term borrowing. Then, my friend and Floridian counterpart Juanita left a huge basketful of grapefruits on the counter, which Emily promptly put to use in a grapefruit-ginger marmalade and a grapefruit white chocolate pie. There are even still a few left, and I’m thinking about making grapefruit tartlets with goat cheese because seriously, it sounds weird, but the combination is uh-mazing. Try this tart, with or without the meringue, and then send me your leftover citrus. I need it. Truly. But an avocado would suffice too.

Grapefruit-Ginger Meringue Tart

Inspired by 101Cookbooks's amazin' curd

I made this first with ginger juice and second by simmering coins of it -- which I liked better -- but either way it’s a light flavor, not too pronounced. If you want it to be gingery as all heck, then start with two tablespoons of ginger juice and increase from there, tasting as you go. And if you’re not a fan of meringue, try this tart with a stripe of powdered sugar on top. Let the tart cool in the fridge for about two hours, then just sift a stripe over the top and serve (instructions below).

For the Crust

9 ounces gingersnap cookies (about 35 li'l cookies), coarsely broken

6 tablespoons butter, melted

1.  Preheat oven to 350 degrees F. Pulverize cookies in food processor. With motor running, pour in melted butter, and pulse until mixture is evenly moistened. Pour crumbs out into 8-inch tart part with removable bottom, and press firmly, evenly to the bottom and up the sides to form your crust. Bake for eight to ten minutes until crust has darkened ever so slightly. If crust falls at all, use the back of a spoon to push it back up the sides. Allow to cool while you work on curd.

For the Curd

1 ½ cups fresh-pressed grapefruit juice (I used CA pink grapefruits, of course)
2 inch knob of fresh ginger, peeled, cut into coins
2 large egg yolks (save whites for meringue)
2 large whole eggs
1 ½ cups water
⅓ cup cornstarch
¾ cup granulated sugar
⅛ teaspoon fine-grain sea salt
5 tablespoons unsalted butter, room temp.
1 teaspoon grapefruit zest

1.  In a medium saucepan, simmer grapefruit juice and ginger coins until juice is reduced to a half-cup. This will take about 30 minutes and helps strengthen the flavor of the grapefruit. Strain out ginger and set juice aside to cool. Crack your egg yolks and eggs into a separate medium bowl, blend gently, and set aside.

2.  Wipe out the medium saucepan you used earlier, and add cornstarch, sugar, and salt.  Gradually blend in the water. Bring to a boil over medium heat, whisking constantly. Continue mixing for two to three minutes until mixture has thickened.

3.  Get your bowl with the yolks and slowly add in the cooled grapefruit juice, whisking all the while. Then slowly add the thickened cornstarch mixture, continuing to whisk. Put this mixture back into the saucepan, reduce heat to low, add your five tablespoons of butter, and whisk gently while cooking for eight more minutes, until mixture is very thick. Remove from heat and stir in zest.

4.  Pour curd into gingersnap crust, press plastic wrap directly to the curd, and get to work on meringue. If skipping meringue, then don’t press plastic to the curd; allow curd to cool to room temperature then refrigerate tart, covered lightly with plastic, for about two hours.  Sift powdered sugar over the top and enjoy!

For the Meringue
5 egg whites, room temperature
1 ¼ cups granulated sugar

1.  Place oven rack in upper third of oven Place egg whites and sugar in the heatproof bowl of an electric mixer set over, but not touching, simmering water. Cook, whisking continuously, until mixture is warm to the touch, about three to five minutes. Transfer mixture to an electric mixer fitted with the whisk attachment, and mix on high until very stiff peaks form.

2.  Place tart on baking sheet. Remove plastic wrap and spoon meringue over top of hot curd, anchoring to crust where possible, and embellishing peaks with a knife or rubber spatula. Broil until meringue is golden brown, about two minutes or so, depending on your oven. Keep your eye on the tart though as you don’t want the meringue to burn! Remove from oven, allow to cool to room temperature, and refrigerate for an hour or two, lightly covered in plastic. Tart will keep covered in the fridge for up to four days.