A 2-quart mold or eight 6-ounce ramekins.

1. In a blender or food processor, process 1 cup of pistachios with all but 2 tablespoons of the sugar. Add the remaining half cup of pistachios and pulse just briefly, so a few good-sized pieces remain.
   
   
2. In the bowl of a stand mixer beat the cream until soft peaks form.
   
   
3. Fold in the ground nuts and grated chocolate.
   
   
4. In another bowl, beat the egg whites with the remaining 2 tablespoons of sugar until semi-stiff.
   
   
5. Fold the egg whites into the whipped cream mixture.
   
   
6. Gently spread into a 2-quart mold or eight 6-ounce ramekins and freeze until firm—about 6 hours.
   
   
7. To unmold, dip the mold in a dish of lukewarm water for 30-60 seconds. Run a knife around the edge and invert.
   
8. Serve immediately.