Combine 1 1/2
cups (375ml) sugar, cornstarch and salt thoroughly in a heavy medium-size
saucepan. Add yogurt, lemon juice and orange juice and stir or beat with
rotary beater until smooth. Set over high heat and cook until mixture
comes to a boil, stirring constantly. Turn heat to low and continue
cooking and stirring 2 minutes longer. Beat egg yolks. Add about half of
the hot mixture to the egg yolks gradually, stirring constantly. Return
the mixture to the saucepan and cook and stir 2 minutes longer. Remove
from heat. Stir in lemon rind. Cool to lukewarm. Pour into
Corn Flake Pie Shell.
Heat oven to
400F (205C). Beat egg whites and cream of tartar until foamy. Add 1/3 cup
(80ml) sugar, about 1 tbsp (15ml) at a time, beating well after each
addition. Continue beating until stiff glossy peaks form. Spread over
filling in pie, sealing to pie shell all around. Bake 8-10 minutes or
until meringue is delicately browned. Cool before serving.