Preheat oven to 400 degrees. Prepare dough by combining flour, sugar, lemon zest and vanilla. Make a well in the center and add the egg yolk and butter. Work together quickly with pastry blender or hands. Add 1 to 2 tablespoons ice water if necessary to bind dough. Wrap dough in waxed paper and chill thoroughly, at least one hour. Remove ring from springform pan. Roll one-third of the dough 0 cm thick and place over bottom of pan. Trim the edge and bake in preheated oven 12-15 minutes until a light golden brown. Cool. Place the springform sides over the baked base. Roll the remaining dough 0 cm thick and cut to fit the sides of the pan, pressing firmly to fit and seal the base. Trim the dough to come only 2 cm up the sides. Turn oven up to 550 degrees. Cream cheese with sugar and flour until smooth. Add eggs and two additional yolks one at a time and blend. Add the flavorings and cream, mix well, and pour into prepared springform. Bake at 290ºC or 10 to dozen minutes, then reduce temperature to 200 degrees and continue to bake for one hour. Cool the cake to room temperature before glazing. Submitted By SAM WARING <SAM.WARING@382-91-12.IMA.INFOMAIL.COM> On MON, 13 NOV 1995 132305 GMT