Coconut Cake with Lemon Curd

6 large eggs, separated
2 1/2 cups (350 grams) all purpose flour
2 teaspoons baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
3/4 cup (170 grams) unsalted butter, room temperature
1 3/4 cups (350 grams) granulated white sugar, divided
1 teaspoon pure vanilla extract
1 1/2 cups (360 ml) buttermilk
1/4 cup (60 ml) canned coconut cream (Coco Lopez is a popular brand) (optional)
1/2 teaspoon cream of tartar
Lemon Curd:
3 large eggs
1/3 cup (80 ml) fresh lemon juice (2-3 lemons) (do not use the bottled lemon juice)
1 tablespoon (4 grams) finely shredded lemon zest
3/4 cup (150 grams) granulated white sugar
4 tablespoons (56 grams) unsalted butter, at room temperature and cut into small pieces
Frosting:
2 large (60 grams) egg whites
1 1/2 cups (300 grams) granulated white sugar
1/4 cup (60 ml) cold water
1 tablespoon light corn syrup
1 teaspoon pure vanilla extract
Garnish:
2 cups (150 grams) sweetened shredded or flaked coconut

Lemon Curd:
In a stainless steel bowl placed over a saucepan of simmering water, whisk together the eggs, sugar, and lemon juice until blended. Cook, stirring constantly (to prevent it from curdling), until the mixture becomes thick (like sour cream or a hollandaise sauce) (160 degrees F or 71 degrees C). This will take approximately 10 minutes. Remove from heat and immediately pour through a fine strainer to remove any lumps. Cut the butter into small pieces and whisk into the mixture until the butter has melted. Add the lemon zest and let cool. The lemon curd will continue to thicken as it cools. Cover immediately (so a skin doesn't form) and refrigerate until cold. The lemon curd can be made several days (up to a week) in advance.
Preheat oven to 350 degrees F (177 degrees C). Butter and flour, and then line the bottoms with parchment paper (or spray with Bakers Joy), two - 9 inch x 1 1/2 inch (23 x 3.75 cm) cake pans. Set aside.

Coconut Cake:

While the eggs are still cold separate the eggs, placing the yolks in one bowl and the whites in another bowl. Cover the two bowls with plastic wrap and allow the eggs to come to room temperature before using (about 30 minutes).
In a mixing bowl sit or whisk together the flour, baking powder, baking soda, and salt. Set aside.
In bowl of electric mixer, or with a hand mixer, beat the butter until soft (about 1-2 minutes). Gradually add 1 1/2 cups (300 grams) of the sugar and beat until light and fluffy (about 2-3 minutes). Add the egg yolks, one at a time, beating well after each addition. Scrape down the sides of the bowl. Add the vanilla extract and beat until combined.
In a small bowl whisk together the buttermilk and coconut cream (if using).
With the mixer on low speed, alternately add the flour mixture and buttermilk mixture, in three additions, beginning and ending with the flour.
In a clean bowl of your electric mixer, with the whisk attachment, (or with a hand mixer) beat the egg whites until foamy. Add the cream of tartar and continue beating until soft peaks form. Gradually add the remaining 1/4 cup (50 grams) of sugar and continue to beat until stiff peaks form. With a rubber spatula gently fold a little of the whites into the batter to lighten it, and then fold in the remaining whites until combined. Do not over mix the batter or it will deflate.
Divide the batter and pour into the prepared pans, smoothing the surface with an offset spatula or the back of a spoon. Bake for about 35 to 40 minutes or until a toothpick inserted into the center of the cake comes out clean and the cake springs back when pressed lightly in center.
Place the cakes on a wire rack to cool, in their pans, for about 10 minutes. Then invert the cakes onto a greased rack. To prevent splitting, reinvert cakes so that tops are right side up. Cool completely before filling and frosting