Portuguese Egg Sweet from the Ritz Hotel

Preheat oven to 350° F. In small, heavy, nonreactive saucepan, combine 1/4 cup sugar with flour and salt, then whisk in milk. Drop in lemon zest and cinnamon stick. Set pan over moderate heat and cook, stirring constantly, until mixture just boils and forms stiff batter, 5 to 7 minutes.

Remove pan from heat and whisk in egg yolks. Set mixture aside to cool, whisking occasionally, 15 minutes.

In large bowl using electric mixer, beat egg whites until fluffy and texture of thick sea foam. Gradually beat in remaining 1/4 cup sugar, then continue beating until soft peaks form.

Remove lemon zest and cinnamon stick from cooled egg yolk mixture and discard. Gently fold 1/3 of beaten whites into yolk mixture. Scoop mixture onto remaining beaten whites and fold in gently but thoroughly until no streaks remain.

Mound batter in ungreased 9-inch ceramic or glass pie pan. Sift ground cinnamon over batter, covering completely. Place pan on baking sheet. Bake on middle oven rack until center is set and cracks have formed on surface, about 30 minutes. Remove from oven and cool to room temperature. ( Sericaia will fall slightly — this is to be expected.) Cut into wedges to serve.

Sericaia will keep, loosely covered, at room temperature up to 2 days.