Make this light, airy and refreshing Orange Creamsicle Cake for a special occasion! It's best to start the cake a day ahead, since you will need to let the filling absorb for at least 10 hours.
Separate 5 eggs while they're cold, adding the yolks to a large bowl (use a stand mixer bowl if you have one) and adding the whites to a large stainless mixing bowl. (It helps to first use two small bowls, adding one egg white at a time to one, and one yolk at a time to the other, then pouring those into your larger bowls as you go. If you get any yolk in an egg white, you can start over with another egg.) Wash your hands after touching raw eggs.
Preheat the oven to 325 degrees F. Grease and flour two, 9-inch, round cake pans.
Rinse an orange and dry it. Grate 1 tablespoon of orange zest and set it aside for the filling.
Squeeze two tablespoons of orange juice and add the juice to your bowl with the egg yolks. Add ½ cup confectioners sugar, the lemon extract, and salt to the egg yolks. Beat the egg yolk mixture for 10 minutes on medium-high speed, until it is very thick and lemon-colored. (If you have a stand mixer, use it.)
If you also have a hand mixer, you can make the meringue while the stand mixer beats the egg yolks. If not, just wait until the egg yolk mixture is done. To make the meringue, using clean beaters and a large, clean stainless bowl, beat the five egg whites and gradually add in the ½ cup of granulated sugar, beating well after each addition. Beat until soft, rounded peaks form. (It will take several minutes. The peaks will turn over slightly when the beater is slowly lifted out of the meringue.)
Gently spread the egg yolk mixture over the beaten egg whites, and gently fold them together, (use an under-and-over motion with your spatula.) Sift the flour into a small bowl (if you have a fine mesh strainer, you can use that to sift). Gradually add the sifted flour to the batter (add ¼ cup of flour at a time), gently folding in the flour as you go.
Transfer the cake batter to the two cake pans, distributing it evenly and smoothing the tops with your spatula. Bake for 15-25 minutes on the center rack (they both should fit diagonally), until a cake tester or toothpick inserted in the center comes out clean. Cool the cake layers by standing them up on a clean towel and letting them lean on a wire rack against your counter's backsplash wall. Turn the pans counter-clockwise occasionally, as the cakes pull away from the edges of the pans.
Orange Meringue Filling
While the cake layers are cooling, make the filling. Squeeze ¾ cup of orange juice and whisk it with ½ cup granulated sugar and the 1 tablespoon of orange zest you prepared earlier. Set that aside.
Separate two eggs, placing the egg whites in a clean and dry medium, stainless bowl. (You won't need the two egg yolks but can refrigerate them for another use.) Using clean beaters, beat the egg whites until frothy, then gradually add in ¼ cup granulated sugar, beating well after each addition. Beat the egg whites until stiff peaks (not dry) are formed. (It will take several minutes. The peaks will remain standing when the beater is slowly lifted out of the meringue.) Add the orange juice mixture to the meringue and gently fold it in until you no longer see any liquid.
When the cake layers have cooled, loosen them from the pans (run a knife around the edges of the pans if you need to). Place a dinner plate over each cake layer and invert one cake layer onto each plate. Carefully turn over each cake layer until the rounded side is up.
Gently spread the orange meringue filling over the surface of each cake layer, starting in the center and being careful not to let the filling run over the sides. If it's runny, you can add some filling, wait a couple of minutes, then add some more in the center so it will stay on the cake. Try to use an equal amount of filling on each layer.
Wash and dry your cake pans and use them to cover each plate. Place the covered cake layers in the refrigerator overnight or for at least 10 hours.
Whipped Cream Frosting
The next day (or after 10 hours), the filling should mostly be absorbed into the cake layers. Make the whipped cream an hour before serving the cake. In a large, stainless mixing bowl (don't use a glass bowl) add the cream and vanilla. Use clean beaters to beat them until frothy. Then gradually add the confectioners sugar while beating the mixture. Beat until you have stiff whipped cream.
To assemble the cake, place one cake layer on your serving dish, with the filling side on top. Gently spread a 1-inch thick layer of whipped cream over the cake's surface. Place the other cake layer on top, keeping the filling side up. Frost the top and sides of the cake, making swirls if you wish. Decorate with orange slices, if desired.
Store the cake in the refrigerator until you're ready to serve it. Cover it with a large mixing bowl if you don't have a cake dome. Store leftover cake covered in the refrigerator for up to four days. It's best not to freeze it because of the whipped cream.
Notes
This cake is best started the day before. Once you make the cake layers and spread on the filling, you will need to let the cake layers absorb the filling overnight, or at least 10 hours. Make the whipped cream and assemble the cake an hour before serving it.Use of raw egg whites in fillingThe filling uses raw, beaten egg whites. For food safety reasons, you may wish to use pasteurized eggs. They will require beating with some cream of tartar in order to whip properly.Use ¼ teaspoon of cream of tartar per large egg white. For the filling, you'd need two large pasteurized eggs and ½ teaspoon of cream of tartar. Add the cream of tartar when the eggs are frothy, and then it will take about 6 ½ minutes to beat into a meringue.If Using Pasteurized Eggs in the Cake Batter There are no raw egg whites in the sponge cake itself. If you decide to use pasteurized eggs anyway, you'll need six large egg whites for the meringue in the batter. You'd need 1 ½ teaspoons of cream of tartar.Recipe Source: Barely adapted from a recipe given to my mother in the 1960s.