Best-Ever Orange Cake
["6 egg whites (3/4 c.)", "1 3/4 c. sifted all-purpose flour", "1/2 tsp. salt", "1 1/2 c. granulated sugar", "6 egg yolks", "6 Tbsp. fresh orange juice", "1 Tbsp. freshly grated orange peel", "confectioners sugar"]
["Place egg whites in large bowl and bring to room temperature, about an hour.", "Measure sifted flour into bowl and set aside. Beat egg whites until foamy.", "Gradually beat in 1/2 cup of the granulated sugar, beating after each addition.", "Continue beating until stiff peaks form.", "Set aside."]
["egg whites", "flour", "salt", "sugar", "egg yolks", "orange juice", "freshly grated orange peel", "confectioners sugar"]