Torta di Ricotta (Makes 8 servings)
3 1/2 cups ricotta cheese
1/2 cup raisins
3 tablespoons dark rum
Fine dry bread crumbs for the pan
5 large eggs, separated
3/4 cup sugar
Grated zest of 1 large lemon
Grated zest of 1 large orange
1/2 cup heavy cream
1/2 cup pine nuts
Place the ricotta in a cheesecloth-lined sieve and place the sieve over a bowl. Cover the ricotta with plastic wrap and let drain in the refrigerator for at least 8 hours or up to one day.
Combine the raisins and rum in a small bowl. Soak, tossing occasionally, until the raisins are softened and have absorbed most of the rum.
Brush an 8-inch spring form pan with enough softened butter to coat lightly. Sprinkle the bread crumbs over the butter to coat generously. Shake out the excess crumbs. Preheat the oven to 375° F.
In a large bowl, beat the egg yolks, sugar and salt with a whisk until pale yellow. Add the drained ricotta, lemon and orange zest and beat until blended thoroughly. Beat in the cream. With a rubber spatula, fold in the pine nuts and the raisins and rum, blending well. In a separate bowl, beat the egg whites with a hand mixer or wire whisk until they form firm peaks when a beater is lifted from them. Add about one fourth of the egg whites to the ricotta mixture and gently stir them in. Add the remaining egg whites and fold them in, using a large rubber spatula to scrape the batter from the bottom of the bowl up and over the whites. Fold just until a few streaks of white remain. Do not overmix. Pour the cake mixture into the prepared pan and bake until the cake is golden brown on top and set in the center, about 1 hour and 10 minutes.
Cool the cake completely before removing the sides of the pan. Serve the cake at room temperature or chilled.