Lemon Ice Cream Pie
["1/3 c. margarine", "2 tsp. grated lemon rind", "1/2 c. lemon juice", "1/4 tsp. salt", "1 c. sugar", "3 eggs", "1 qt. vanilla ice cream, softened but not thawed", "1 (9-inch) pastry shell, baked and cooled", "3 egg whites", "1/2 c. sugar"]
["Combine margarine, lemon rind, lemon juice, salt, 1 cup sugar and eggs in double boiler until thick.", "Cool.", "Place half of custard in baked pie shell.", "Top with half of the ice cream. Freeze, then add rest of custard and ice cream.", "Refreeze."]
["margarine", "lemon rind", "lemon juice", "salt", "sugar", "eggs", "vanilla ice cream", "pastry shell", "egg whites", "sugar"]