In a heavy bottomed saucepan stir together the fillings ingredients. Stirring constantly, cook over medium heat until thickened and bubbly. Keep warm.
For the meringue, beat together egg whites and cream of tartar. Beat on medium speed until soft peaks form. Add sugar 1 tablespoon at a time. Beat on high for 4 minutes, or until stiff, glossy peaks form.
Pour warm filling into baked pie shell. Spread meringue over filling.
Bake for 15 minutes, or until meringue is browned.
Cool 1 hour on a wire rack. Chill 4 to 6 hours before serving.