Macadamia Rum Mousse Pie

Preheat the oven to 400 degrees. For the crumb crust, combine the
nuts, flour, salt, sugar, and cinnamon in a mixing bowl, and stir to
mix well. Stir in the melted butter and continue stirring until the
mixture has absorbed the butter. Break the mixture into even 1/2 to
1/4 inch crumbs, rubbing with the fingertips. Place half the crumb
mixture into a 9 inch Pyrex pie pan and press with the fingertips to
line the pan evenly. Place the remaining crumb mixture, in an even
1/2inch layer on a cookie sheet. Bake the crust and crumbs on the
middle rack of the oven about 20 minutes, until crisp and light
golden in color. Cool the crust and crumbs on racks. For the Mousse
Filling, whip the cream until it holds soft peaks and set it aside in
the refrigerator. Sprinkle the gelatin on the water in a small,
heatproof bowl. Allow to soak 5 minutes, then place over a small pan
of simmering water to melt while preparing the filling. When the
gelatin is melted, remove from the pan and allow to cool. In the bowl
of an electric mixer, or another heatproof bowl, whisk the egg yolks.
Whisk in the rum, then the sugar. Place over a pan of gently
simmering water and whisk constantly until thickened, about 3
minutes. If the yolk mixture becomes too hot, it may scramble. Remove
the bowl from the water and beat by machine, on medium speed, until
cooled to room temperature. Whisk in the dissolved gelatin, then fold
in the whipped cream and the chopped nuts. Pour the filling into the
cooled shell and smooth the top. Cover loosely with plastic wrap and
chill until set at least 6 hours. To finish the pie, top with the
baked crumbs. Or whip the optional cream, spread half on the mousse
and top with the crumbs. Then, pipe a border of rosettes of the
remaining cream around the edge of the pie with a pastry bag fitted
with a star tube. Yield: one 9 inch pie