Ricotta Pie
["2 c. Ricotta (whole milk)", "4 to 6 egg yolks", "1/2 c. sugar, divided", "1/2 c. flour", "1 c. golden raisins, soaked in Marsala wine", "4 to 6 egg whites", "1/4 c. rum (optional)", "1 tsp. lemon zest or lemon extract"]
["Beat egg whites until stiff with 1/4 cup sugar. Mix cheese, sugar and flour until smooth. Mix in all ingredients, except egg whites.", "Fold in egg whites. If batter is too stiff, add another egg yolk or rum.", "Grease and flour spring-form pan. Bake at 375\u00b0 for 30 to 40 minutes."]
["Ricotta", "egg yolks", "sugar", "flour", "golden raisins", "egg whites", "rum", "lemon zest"]