Crumble mincemeat into a saucepan. Add ½ c. water and cook, stirring, until lumps are broken and mixture comes to a boil. Boil vigorously 1 minute. Cool.
Dissolve gelatin in hot water. Chill until spoonful of mixture mounds slightly. Fold in mincemeat and walnuts, then whipped cream.
Pour into pie shell. Chill until firm. (Garnish with additional whippe