3 eggs, separated
1 (11 oz.) can sweetened condensed milk
1/4 c. Key Lime or Persian Lime juice
1/2 tsp. sugar
1 (9-inch) graham cracker crust

Preheat oven to 400 degrees. Beat together the egg yolk and condensed milk. Add the lime juice; beat until smooth. Pour mixture into baked pie crust. To make meringue, beat the egg whites until stiff, but not dry. Add sugar, beating constantly. Swirl on top of lime custard. Bake until the meringue is brown.