4 eggs
1 can sweetened condensed milk
1/2 c. lime juice (key lime if possible)
6 tbsp. sugar
1/2 tsp. cream of tartar

Preheat oven to 250 degrees. Beat 4 egg yolks, add condensed milk and lime juice, beat until thick, pour into baked pie shell. For topping, beat 4 egg whites, blend in sugar and cream of tartar, beat until stiff and forms peaks. Bake in moderate oven until egg whites are golden brown.