Mix together sherry, orange juice, cream and gelatin in the top of a double boiler. To the mixture add pumpkin, 1/2 cup brown sugar, egg yolks, cinnamon, salt, ginger, nutmet and orange rind. Place over boiling water and cook stirring occasionally until filling thickens slightly, about 10 minutes. Remove from heat and cool.
Beat egg whites to soft peaks, about 5 minutes with a mixer. Then beat in remaining 1/4 C sugar to make meringue. Fold meringue into pumpkin filling.
Set aside 1 1/2 cup of pumpkin meringue. Turn remainder of filling into pie shell. Place into refrigerator to chill quickly. Beat 1/2 cup cream until stiff. Fold into reserved pumpkin filling. Gently spoon on filling into pastry shell. Return to refrigerator and chill until firm (3-4 hours.) Garnish pie with remaining 1/2 cup cream, beaten stiff and slightly sweetened if desired just before serving.
Allegedly the trick behind whipping actual cream for the topping is to make it cold, cold, cold including the utensils. The trick for meringue is to have everything at room temperature. Funny how that works, isn't it?