Lemon Pie

1 10 inch pie crust
2 cups sugar
½ cup cornstarch
2 cups water
4 egg yolks, beaten
¼ cup butter
2 teaspoons lemon zest
2/3 cups lemon juice

Mix sugar and cornstarch in medium saucepan. Stir in water and cook over medium heat, stirring constantly until the mixture thickens. Bring to a boil and let boil for 1 minute while stirring. Gradually stir in egg yolks and blend into mixture. Boil and stir for 2 minutes. Remove from heat. Stir in butter, zest and juice. Pour into crust.

Variations:
Mix 1 package cream cheese with 1 tub Cool Whip and layer in the bottom of the crust before adding the lemon filling.

Layer ½ of the filling in the bottom of the crust. Mix the other half with sour cream and pour over the first half.