If madadamia nuts are salted, spread on towel and rub to remove as much salt as possible.
Chop nuts and place in single layer on baking sheet.
Toast about 5 minutes, or until golden brown. Set aside.
Combine sugar, gelatin, cornstarch and salt in blender or food processor.
Add cream cheese and sour cream.
Whirl, gradually adding milk, and continue blending or processing until smooth.
Note: If using a food processor, add part of the milk, process and pour part of the mixture into top of a double boiler, then add remainder of milk and process. This will prevent an overflow from too much liquid.
Place mixture in top of double boiler and cook over gently boiling water until thick and smooth, stirring constantly, about 15 minutes.
Whisk some of the mixture into egg yolks. Return to pan, whisking as it continues to cook, about 3 minutes.
Remove top of double boiler and set aside to cool slightly.
Whip egg whites until stiff peaks form.
Stir rum into filling mixture and fold in egg whites.
Chill until thickened but not firm.
Whip cream until stiff and fold into filing along with half of the toasted nuts.
Pour into prepared crust and chill at least 2 hours.
Sprint top with remaining nuts just before serving.