1 teaspoon grated lemon rind or 1/4 teaspoon lemon extract
2 eggs, separated
1 (8- or 9-inch) graham cracker or baked pie crust
1/4 teaspoon cream of tartar
4 tablespoons sugar
Preheat oven to 325°F. In medium bowl, combine sweetened condensed milk, lemon juice, lemon rind or extract and egg yolks; stir until mixture thickens. Pour into chilled graham cracker crust or cooled pie crust.
In medium bowl, beat egg whites and cream of tartar on high speed until soft peaks form. Gradually beat in sugar on medium speed, 1 tablespoon at a time; beat 4 minutes longer or until sugar is dissolved and stiff glossy peaks form.
Spread meringue over pie, carefully sealing to edge of crust to prevent meringue from shrinking. Bake 12 to 15 minutes or until meringue is lightly browned. Cool. Store leftovers covered in refrigerator.