Instructions

• Preheat the oven to 350°F. Place an oven rack in the lower-middle position. Have a 10-inch angel food (tube) pan ready — do not grease or spray it.
• Sift the 1 cup unbleached all-purpose flour into a bowl and set aside.
• Sift the 1 1/2 cups powdered sugar and keep it nearby for adding.
• In a large mixing bowl, combine the 1 1/2 cups egg whites (see ingredient list: 10–12 egg whites), the 4 teaspoons lime zest, and the 4 1/2 teaspoons fresh lime juice. Using the whisk attachment on a stand mixer or an electric hand mixer, beat on medium speed until the mixture is foamy.
• With the mixer running, gradually add the sifted powdered sugar a little at a time (about 1–2 tablespoons per addition) until all the sugar is incorporated. Continue beating until the egg whites are glossy and hold stiff peaks (this can take about 8–12 minutes).
• Place the sifted flour into a fine-mesh sieve or sifter. Add the flour to the whipped egg whites in three equal additions: sift the first third over the whites, then gently fold it in with a rubber spatula using a low, under-and-over motion. Repeat with the second and third additions, folding just until each addition is incorporated. Stop as soon as there are no visible dry streaks; do not deflate the batter.
• Gently transfer the batter into the ungreased 10-inch angel food pan, spreading evenly. Lightly tap the pan on the counter a few times to settle the batter and remove any large air pockets. Do not spray or grease the pan.
• Bake at 350°F for about 40 minutes, or until the top is light golden brown and the cake springs back when lightly touched.
• Immediately after removing the cake from the oven, invert the pan and set it upside down on a bottle, the pan’s feet, or a cooling rack so the cake is suspended while cooling. Leave the cake inverted and cool completely in the pan.
• Once completely cool, run a thin spatula or knife around the center tube and outer edge if needed to loosen, then remove the cake from the pan, slice, and serve.