Ingredients

1 1/4 cups sifted cake flour 

1 1/2 cups sugar, divided 

1 1/4 teaspoons kosher salt (we use Diamond Crystal), divided 

12 large egg whites, plus 6 large yolks 

1 1/2 teaspoons finely grated lemon zest, plus 2 tablespoons fresh juice 

1 teaspoon finely grated orange zest, plus 1 tablespoon fresh juice 

1 teaspoon cream of tartar 

Edible pansies, for serving (optional) 

2 cups sifted confectioners' sugar, plus more if needed 

2 tablespoons fresh lemon juice, plus more if needed 

1/2 teaspoon grated orange zest, plus 1 tablespoon fresh juice 

1 teaspoon orange-blossom water (optional) 

2 tablespoons unsalted butter, melted 

Pinch of kosher salt

Preparation

For the Cake: Preheat oven to 350°F. Sift flour, 1/4 cup sugar, and 1 teaspoon salt through a coarse-mesh sieve onto a piece of parchment. Beat yolks and 1/4 cup sugar with an electric mixer on high speed until doubled in volume, 3 minutes. Beat in both zests and juices.

In a clean bowl with clean whisks, beat egg whites on high speed until foamy. Beat in remaining 1/4 teaspoon salt and cream of tartar until soft peaks form. Gradually add remaining 1 cup sugar; beat to stiff peaks. Transfer to a large, wide bowl. Sift one-third of flour mixture over top; gently but thoroughly fold in. Repeat twice more with remaining flour mixture.

Fold half of egg-white mixture into yolk mixture; dollop into an ungreased 10-inch angel-food-cake pan. Top with remaining egg-white mixture. Run a knife through to release air bubbles. Bake until top springs back when lightly touched, 35 to 40 minutes.

Invert pan onto its legs (or rest on the neck of a wine bottle); let cool 1 hour. Run a knife around inside of pan and tube to release cake and unmold, then use it to release cake from pan bottom; remove.

For the Glaze: Whisk together all ingredients to create a thick but pourable glaze. If too thick, whisk in more lemon juice, 1 teaspoon at a time; if too thin, more confectioners’ sugar. Place cake on a cake stand and pour glaze over top, letting it drip down sides. Let stand until set, about 30 minutes; decorate with flowers.