Not everyone has the "so many egg whites, not enough uses for them" problem, but those that do (like me!) generally have it in a bad way. All of you who thus far have been spared such a predicament might not even conceptualize how it comes about. But bake your way through enough of my cake recipes - and in particular, cake fillings - and you will rapidly amass a freezer full of leftover egg whites from all the yolks that are siphoned off for custards and curds or even just glazing a loaf of bread.
Sure, some of those very same cakes need a meringue frosting to go with them. And at least one of every five dozen egg whites deserves to become an angel food cake to accompany some glorious summer berries. But then things can start to get tricky. Last spring, I was pleased to find this excellent article, with a number of solid suggestions for "the other half," but none of these recipes really spoke to me (excepting the spiced nuts, but those are already a frequent part of my repetoire and one large batch still only uses one solitary egg white.)
There must be another way! Yes, it's still cake (do I lose points for that?) I found inspiration from many sources - primarily an egg-white-only spice cake in The Cake Bible, and the pith-peel-and-all Satsuma Cake, but I truly take complete credit for developing this recipe myself. This is nothing like a sticky-sweet airy-puff of angel food. It needs no accompaniment, but would be excellent with just a dusting of powdered sugar or a drizzle of dark chocolate sauce. With a delicious touch of bitterness, like marmelade, this moist, flavorful orange cake has a great texture with a golden "crust" but soft and dense interior. The layers are shallow, so did not make for a glamourous dinner party dessert, but are pefect with tea for breakfast or a snack. I might also try baking all the batter one pan for a more substantial presentation. [I'm not sure that the egg whites will provide enough structure to keep it from collapsing... I'll let you know if I try it, or you can test it yourself and post the results in the comments here. It would need to bake longer, and maybe start at a higher temperature then lower oven to try and prevent sinking.]
1 cup orange puree (about 1 1/2 medium oranges) - remove seeds, but throw everything else in to the food processor... pith, peel, the works.
135 grams egg whites (1/2 cup or about 4 large)
1/4 cup milk
300 grams all-purpose flour (2.1 cups)
300 grams sugar (1.56 cups)
12 tablespoons unsalted butter, softened
1 teaspoon baking soda
1/8 teaspoon baking powder
3/4 teaspoon salt
1/2 teaspoon ground cloves
Butter and flour two 9-inch cake pans, with removeable bottoms (or line with parchment). Preheat oven to 350 degrees. Combine egg whites with 1/4 cup of orange puree and milk. In separate bowl, whisk together dry ingredients (flour, sugar, soda, powder, salt, and cloves). Add softened butter and remaining 3/4 cups orange puree and blend until well combined. In three additions, blend in egg mixture, beating well after each addition to incorporate and develop structure of batter. Divide evenly into prepared pans and bake about 30 minutes, until tops are golden and tested inserted in center comes out clean. Cool in pans on rack for 15 minutes, then invert.