Active Time

　　45 min

　　Total Time

　　15 hr

　　

Ingredients

Makes 8 to 10 servings

　　

For crust

1/2 cup all-purpose flour

　　2 tablespoons sugar

　　1/2 teaspoon salt

　　5 tablespoons cold unsalted butter, cut into bits

　　1 large egg yolk

　　1/2 teaspoon vanilla

　　1/2 teaspoon fresh lemon juice

　　

For filling

2 lb whole-milk ricotta, drained in a cheesecloth-lined sieve set over a bowl at least 6 hours, chilled

　　6 large eggs, separated

　　3/4 cup sugar

　　3 tablespoons all-purpose flour

　　Finely grated zest of 1 lemon

　　Finely grated zest of 1 orange

　　1/8 teaspoon salt

　　

Step 1

Preheat oven to 350°F.

　　

Make crust:

Step 2

Pulse flour, sugar, salt, and butter in a food processor until mixture resembles coarse meal. Add yolk, vanilla, and lemon juice and pulse just until mixture begins to form a dough. Spread dough with a small offset spatula or back of a spoon over buttered bottom of a 24-centimeter springform pan and prick all over with a fork. Chill 30 minutes.

　　

Step 3

Bake crust in a shallow baking pan (to catch drips) in middle of oven until golden brown, about 25 minutes, and cool on a rack.

　　

Step 4

Increase temperature to 375°F.

　　

Make filling and bake cake:

Step 5

Discard liquid and cheesecloth and force drained ricotta through sieve into bowl. Beat yolks and sugar with an electric mixer until thick and pale, then beat in ricotta, flour, and zests. Beat whites with salt in another bowl until they hold soft peaks, and fold into ricotta mixture.

　　

Step 6

Butter side of springform pan and pour filling over crust (pan will be completely full). Bake in baking pan in middle of oven until cake is puffed and golden and a tester inserted 1 inch from center comes out clean, about 1 hour.

　　

Step 7

Run a knife around top edge of cake to loosen and cool completely in springform pan on rack. Chill, loosely covered, at least 4 hours. Remove side of pan and transfer cake to a plate. Bring to room temperature before serving.

　　Cooks' note:

　　Cheesecake keeps, covered and chilled, 3 days.