|Letting the cake cool in an ungreased tube pan|
1 ½ cups sifted cake flour
1 cup granulated sugar, divided
2 teaspoons baking powder
½ teaspoon salt
5 tablespoons unsalted butter, melted
1 teaspoon grated orange zest
1/3 cup strained fresh orange juice
6 large eggs, separated
1 teaspoon vanilla extract
½ teaspoon cream of tartar
1 cup sifted confectioners’ sugar
1 teaspoon orange zest
2 tablespoons fresh orange juice
1. Position a rack in the center of the oven and preheat to 350˚F. Have ready an ungreased 10-inch tube cake pan with a removable bottom. (Do not use a tube pan with a nonstick surface.)
2. Sift the flour, ½ cup sugar, the baking powder and salt into a medium-sized bowl. Form a well in the center and add the melted butter, orange zest, orange juice, egg yolks and vanilla. With an electric mixer, beat until smooth, 1 to 2 minutes.
3. In a large bowl combine the egg whites and cream of tartar; beat with an electric mixer until soft peaks begin to form. Gradually beat in the remaining ½ cup sugar and continue to beat until stiff glossy peaks form. Stir a large spoonful of the whites into the batter to lighten. With a spatula, quickly fold in the remaining egg whites, half at a time, to make a fluffy batter that is even in color. Turn into the ungreased tube pan and bake 1 hour to 1 hour and 15 minutes, until the top springs back when lightly touched and a toothpick inserted emerges without crumbs clinging to it. Immediately invert and let the cake hang upside down until completely cool. Turn right side up and run a sharp knife around the edge to separate the cake from the pan. Remove sides. Run a knife around the center tube and under the cake; remove the pan bottom. Turn the cake right side up on a serving plate.
4. Prepare glaze: In a small bowl combine the confectioners’ sugar, orange zest, and orange juice to make a glaze. Spread over the top of the cake, letting some drip down the sides. Let stand at room temperature until glaze has set, about 1 hour.