Lemon Meringue Pie

1 14oz can sweetened condensed milk
1/2 c lemon juice
1 t grated lemon zest
3 egg yolks
1 prebaked pie shell

Meringue:
3 egg whites
1/4 t cream of tartar
1/4 c sugar

In a medium bowl, combine milk, lemon juice and zest; blend in egg yolks. Pour into cooled crust. Preheat oven to 325F. Beat egg whites with cream of tartar until soft peaks form. Gradually beat in the sugar until stiff. Spread over filling, seal to edge of crust. Bake 12-15 min. or until meringue is golden brown.