Step 1

Heat the oven to 325°F with a rack in the middle position. Have ready an ungreased 9-inch or 10-inch tube pan with a removable bottom or, if using a 1-piece pan, line it with kitchen parchment cut to fit into the bottom, with a center hole to accommodate the tube. In a medium bowl, whisk together the flour, baking powder and salt; set aside.

Step 2

In a small saucepan over medium, heat the milk to just below a simmer (185°F), 2 to 3 minutes. Set aside off heat.

Step 3

In a stand mixer with the paddle attachment, beat the egg yolks, 214 grams (1 cup) of the white sugar and the orange zest on medium-high until the mixture is pale yellow and doubled in volume, 3 to 4 minutes. Scrape down the bowl. With the mixer running on low, drizzle in the warm milk very slowly, then add the vanilla and beat until combined, about 1 minute. Scrape down the bowl. With the mixer running on low, add the flour mixture in three additions, mixing until almost fully incorporated, about 30 seconds, after each addition. Remove the bowl from the mixer and fold with the spatula to ensure no dry pockets remain. Transfer the mixture to a large bowl; set aside. Thoroughly wash and dry the mixer bowl.

Step 4

In the clean mixer bowl, using the whisk attachment, whip the egg whites on medium-high until light and foamy, about 1 minute. With the mixer running, slowly sprinkle in the remaining 214 grams (1 cup) white sugar and continue to whip until the whites are thick and glossy and hold very droopy, soft peaks, about 2 minutes. Remove the bowl from the mixer.

Step 5

Using the spatula, fold one-third of the egg whites into the batter until mostly combined. Gently fold in the remaining whites until no streaks remain; the batter will be light and airy but pourable. Pour the batter into the tube pan and spread it into an even layer.

Step 6

Bake until the cake is golden brown and a toothpick inserted 2 inches from the edge comes out clean, 50 to 55 minutes if using a nonstick pan, or 55 to 60 minutes if using a conventional pan. Immediately invert the pan onto a heatproof surface and let the cake cool to room temperature, about 1 hour.

Step 7

Invert the pan again. Run a long, thin knife between the cake and the sides the pan as well as between the cake and the center tube. If you’ve used a pan with a removable bottom, lift out the center tube with the cake attached and set it on a surface. Slide the knife between the cake and the base to loosen. Invert the cake still on the base onto a platter, then lift off the base. If you’ve used a one-piece pan, after loosening the sides of the cake, invert the pan onto a platter, lift off the pan and peel off the parchment. If desired, dust the cake with powdered sugar just before serving.