2 1/4 c. cake flour
1 1/4 and 1/4 cups sugar, divided
1 T. baking powder
1 t. salt
3/4 c. cold water
1/2 c. vegetable oil
1 t. lemon zest
1 t. vanilla extract
5 large egg yolks at room temperature
8 large egg whites at room temperature
1/2 t. cream of tartar
For the custard:
6 large egg yolks
1/2 c. sugar
2 c. half and half
3 T. cornstarch
For the macerated strawberries:
3 lb. strawberries
2 T. sugar
For the whipped cream:
2 c. chilled heavy cream
1 T. sugar
Make the custard: (you can do this step the night before)
Whisk together all of the custard ingredients in a saucepan. Bring the mixture to a boil over medium-low heat, whisking constantly. Turn down the heat so that the mixture just simmers, and whisk until thick, 1-2 minutes. (The key words here are whisk constantly. The custard will tell you in no uncertain terms when it is done. It's like magic. One moment you can comfortably whisk your way through the liquid, and the next it is undeniably a thick custard. Cornstarch is neat like that.) Transfer the custard to a bowl, cover with plastic wrap or a round of wax paper, and cool. Then, chill custard, covered, for at least 3 hours, or up to 2 days.
Bake the cakes: (you can also do this step the night before)
Preheat the oven to 325 degrees. Line the bottoms of two 9-inch round cake pans with lightly oiled (I use cooking spray) parchment paper . Otherwise, leave the pans ungreased.
Sift together the flour, 1 1/4 c. sugar, baking powder, and salt twice into a large bowl.
In a separate bowl, use an electric hand mixer on high speed to beat together the yolks, water, oil, zest, and vanilla until smooth. Stir into the flour mixture.
In another large bowl, or the bowl of a stand mixer, beat the egg whites with the cream of tartar until soft peaks form. Add the remaining 1/4 c. sugar, and beat on high until the peaks are stiff but not dry.
Using a rubber spatula (and a very light touch), fold about a quarter of the fluffy egg whites into the egg yolk mixture. Then fold in the remaining whites. Be very gentle. The goal here is to incorporate the egg whites without allowing them to deflate significantly. It is all of the air that has been whipped into the egg whites that will make for tall and light cake layers. As soon as the egg whites are no longer visible, stop folding.
Scrape the batter into the two prepared pans and spread evenly. (Here is a trick for making sure you have poured an equal amount of batter into each pan: Grab two toothpicks and stick one into the center of each batter-filled pan. Then, pull them out and see if the amounts of batter on the picks line up.) Bake for approximately 35 minutes, until the top springs back when lightly pressed and a toothpick inserted into the center comes out clean.
For the next step, and for the splitting, wax paper is your friend. Any surface that carries a cake layer, I line with wax paper for easier transfer.
Allow the cakes to cool in their pans on a cooling rack for at least an hour. When completely cool, run a knife around the sides to release the cakes, cover each pan with a wax paper-lined plate, and flip. Gently lift the pans off of the cakes, and carefully peel back the pieces of parchment, taking care not to take the very tops of the cake with you. (I did end up pulling off a teeny tiny bit of the top of one layer, but it didn't matter, since the cake would ultimately be covered in whipped cream.)
Wrap the two cakes in plastic wrap, and refrigerate at least three hours, or overnight.
Meanwhile, prepare the strawberries:
Slice the strawberries thinly (but not too thinly - you want the slices thick enough so that you can really taste and feel the berries even once they are smothered by custard, cake, and whipped cream!), and place in a bowl. Sprinkle with the 2T. sugar, and stir. Allow the strawberries to macerate for 1 hour. Their juices will release and pool at the bottom of the bowl. Every so often, give them a stir. Strain the berries, reserving the released juices.
When the cakes are thoroughly chilled, and thus a little sturdier, it's time to split them in two. Using a long serrated bread knife, carefully saw each layer in half. Place each layer on a wax paper-lined baking sheet or plate.
Whip the cream:
Whip the cream and sugar together until stiff.
Assemble the cake!
(I experimented with my layering technique: custard alone between the first and second layers, strawberries alone between the second and third layers, and strawberries and custard between the third an fourth layers. In the future, I'll put strawberries and custard between every layer.)
Place one cake layer on a wax paper-lined baking sheet. Brush the top of the layer with 1/3 of the reserved strawberry juice. Cover with a layer of strawberries, and then with a layer of custard. Top with the next layer of the cake, and repeat: strawberry juice, strawberries, custard, cake layer. And again.
Using a spatula, cover the entire cake with whipped cream. Top with either leftover macerated strawberries, or a few "raw" strawberries. (Next time, I'll go with the latter.)
Chill the cake for at least 8 hours before serving, so that the cake has time to absorb the strawberry juices. Bring to cool room temperature before serving.
(To transfer the cake from the baking sheet to a cake stand, use the wax paper to gently scooch the cake from one surface to the other, then tear away the visible wax paper.)
