Lemon Butter Cream Pie

1/2 cup butter
1 cup granulated sugar
2 eggs
2 egg yolks
6 tablespoons lemon juice
2 teaspoons grated lemon rind
1 (8-inch) pie shell, baked
2 egg whites
1/8 teaspoon salt
1/4 cup granulated sugar

Cream butter and sugar until light and fluffy. Add eggs and yolks, one at a time, beating well after each addition. Blend in lemon juice and rind. Cook in double boiler over hot water, stirring constantly, until thickened. Cool slightly. Pour into cool pie shell.

Add salt to egg whites and beat until frothy. Beat in sugar, a tablespoon at a time, continuing to beat mixture will hold soft peaks. Spread over filling, sealing carefully to crust. Bake at 325 degrees F for 12 to 15 minutes or until nicely brown.