4 eggs, separated
1 (14 oz.) can sweetened condensed milk (Eagle Brand)
1/2 c. Key lime juice
1 (9-inch) graham cracker pie crust
1/8 tsp. cream of tartar
1/4 c. plus 2 tbsp. sugar

Beat egg yolks until thick and lemon colored. Add milk and lime juice; blend well. Spoon filling into graham cracker pie crust. Combine egg whites (at room temperature) and cream of tartar. Beat until foamy. Gradually add sugar, one tablespoon at a time. Beat until stiff peaks form. Spread meringue over filling; seal to edge of pie crust.

Bake at 350°F for 10 minutes (until meringue is golden brown). Cool to room temperature. Chill in the refrigerator.