Orange Custard Cream Pie

1 (14 ounce) can sweetened condensed milk
4 eggs, separated
1/2 cup orange juice
2 tablespoons orange liqueur
1 (9-inch) pie shell, baked
1/2 cup granulated sugar
1/2 teaspoon cream of tartar
Pinch of salt

Preheat oven to 350 degrees F.

Filling: Stir together sweetened condensed milk, egg yolks, orange juice and orange liqueur. Pour into the prepared pie shell and bake for 15 to 20 minutes, until just set. Remove from the oven and increase oven temperature to 450 degrees F.

Meringue: Combine egg whites and sugar in a metal bowl. Set in a pan of simmering water (or place the pan directly over lowest heat if desired) and stir for a minute or two until the sugar has dissolved and the mixture is warm. Remove from heat. Add cream of tartar and salt, and beat until the meringue stands in soft peaks. Spread over the pie and return to the oven for about 5 minutes, until golden. Cool to room temperature.