Combine flour, sugar, salt, lemon peel and vanilla. Cut in butter and egg yolks with pastry blender until well blended.
- Put about ¼ c. mixture in each of 10 well-greased 5 oz. custard cups. Pat mixture evenly into bottom and sides to line cups. (Dip fingers in water to keep them from sticking.)
- Chill at least 1 hour.
Beat softened cream cheese until light and fluffy. Gradually add mixture of sugar, flour and salt, beating smooth after each addition. Beat in lemon peel and vanilla. Add eggs, one at a time, and egg yolk, beating well after each addition. Beat in cream.
- Spoon into lined custard cups.
- Bake in extremely hot oven (500°F.) 10 minutes. Reduce heat to 350°F. and continue baking until golden brown, 20 to 25 minutes. (There will be cracks in cheese filling.)
- Cool at room temperature. Carefully remove from custard cups and chill thoroughly.
- To serve, top with a little dairy sour cream and a spoonful of colorful jam, jelly or fruit preserves. Or top with fresh or frozen fruit.