Full Moon Cake

Ingredients

• 2½ cups cake flour
• ½ cup unrefined sugar
• 2 teaspoons baking powder
• ¾ teaspoon sea salt
• Zest of 1 lemon
• 5 egg yolks, room temperature
• 1 teaspoon vanilla
• ¾ cup whole milk, room temperature
• ¼ cup olive oil
• 9 egg whites, room temperature
• ¼ teaspoon cream of tartar
• A 9" springform pan

Steps

1. Arrange a rack in center of oven; preheat to 325°. Cut a 9" circle of parchment to cover bottom of springform pan. Grease pan with butter, dust with flour, and set parchment inside.
2. Sift sugar, baking powder, salt, and remaining 2½ cups flour into a medium bowl. Stir in lemon zest.
3. Whisk egg yolks and vanilla in a medium bowl. Add milk and whisk to combine, then add oil and whisk again to combine.
4. Pour yolk mixture into dry ingredients. Fold batter with a wooden spoon, scraping bottom and sides of bowl, until creamy, glossy, and fully combined (about 6–7 folds).
5. Using an electric mixer on medium-high speed, beat egg whites in a large bowl until soft peaks form. Add cream of tartar and continue to beat until stiff peaks form (do not overbeat; it will dry out the egg whites).
6. Using a large spatula, fold one-third of egg whites into batter to lighten. Fold in remaining egg whites in two additions until batter is bubbly, shiny, and loose.
7. Pour batter into prepared pan and bake cake until a tester inserted into the center comes out clean, 45–50 minutes.
8. Run a very sharp knife between edge of cake and pan. Let cool in pan until cool to the touch, about 1 hour.
9. Carefully remove adjustable body of springform pan and invert cake onto a platter. Peel off parchment. Serve plain or top with whipped cream or icing, if using.