Separate the eggs and beat the yolks. Add 1/2 cup sugar, the pumpkin, milk, salt and spices. Cook in a heavy saucepan until thick, stirring frequently. Remove from heat.
Into the 1/4 cup cold water, sprinkle the gelatine and mix well. Add this to the hot pumpkin mixture. Mix thoroughly and cool.
While waiting for mixture to cool, beat the egg whites until stiff, adding the remaining 1/2 cup sugar halfway through. Fold this into the cooled pumpkin mixture.
Pour into the previously baked (or your graham cracker crust) pie shell. Chill overnight. Serve with Cool Whip, whipped cream, or ice cream on top.
You can also forget about the pie shell and just make the filling and eat like a pudding or use for a parfait. Very light and tasty.