Instructions

1. Heat the oven to 350°F.
2. Beat 12 room temperature large egg whites in a stand mixer fitted with the whisk attachment on low speed until foamy bubbles have formed, about 2 minutes.
3. Add 1 1/2 teaspoons cream of tartar and 1/4 teaspoon kosher salt. Beat on medium-high speed until soft peaks form, 1 to 2 minutes.
4. With the mixer on medium speed, slowly pour in 1 cup granulated sugar and beat until combined, about 30 seconds total.
5. Scrape down the bowl with a flexible spatula. Add 1/2 teaspoon almond extract and 1/2 teaspoon vanilla extract. Beat on medium-high speed until stiff peaks form, 2 to 3 minutes.
6. Turn off the mixer. Sift 1 cup cake flour and 1 cup powdered sugar directly into the bowl. Gently fold them in by hand with the spatula until just combined. (If your mixer doesn’t have a lot of room after the egg whites are whipped, transfer them to a larger bowl first before folding in the cake flour and powdered sugar.)
7. Transfer the batter into 1 (about 10-inch) ungreased tube pan with a removable bottom. Gently run a knife through the batter to pop any air bubbles, then smooth out the top.
8. Bake until the top is golden-brown and springs back slightly when you touch it, 40 to 45 minutes.
9. Immediately invert the pan on a wire rack and let the cake cool upside-down in the pan until still a little warm to the touch, about 1 hour.
10. Flip the pan right-side-up. Carefully run a thin knife around the edges of the cake to release it from the sides of the pan. Remove the cake and tube insert from the pan, then use the knife to release the cake from the bottom of the insert as well