Pumpkin Chiffon Pie

3 beaten egg yolks
3/4 cup brown sugar
1 1/2 cups canned pumpkin
1/2 teaspoon salt
1 teaspoon cinnamon
1/2 teaspoon nutmeg
1/2 cup milk
1 envelope plain gelatine
1/4 cup cold water
3 stiffly beaten egg whites
1/4 cup granulated sugar
1 (9-inch) baked pie shell

Combine first 7 ingredients. Cook in double boiler until thick, stirring constantly. Soak gelatine in cold water. Mix into hot mixture. Chill until partially set. Beat egg whites; add sugar, and beat until stiff. Fold into pumpkin mixture. Pour into cooled pie shell and chill until set. Garnish with whipped cream.