1. For the crust: Mix all of the ingredients together until smooth. Press into the bottom of a lightly greased 9" springform pan or 9" pie pan. Prick all over with a fork, then freeze for 30 minutes.

  2. While the crust chills, preheat the oven to 400°F.

  3. Bake the chilled crust for 15 to 18 minutes, until set and no longer wet-looking in the center. You should smell chocolate when it's done. Remove from the oven and let cool completely.

  4. For the filling: Combine the eggs, egg yolks, and confectioners' sugar in a heatproof bowl.

  5. Place the bowl over simmering water and beat until thickened and the temperature reaches 165°F when measured with a digital thermometer.

  6. Remove from the heat and stir in the pistachio paste until evenly combined.

  7. Place the bowl in a pan of ice water to cool, stirring occasionally.

  8. In a separate bowl, whip the heavy cream to medium peaks, then fold it into the cooled pistachio mixture.

  9. Scoop the filling into the cooled crust and smooth the top.

  10. Freeze for 6 hours before serving.

  11. To serve: Run a thin spatula around the outside edge of the cake to separate it from the side of the springform pan (if using), then release the springform clip. Remove the side of the pan and sprinkle chopped pistachios on top before slicing.

  12. Store covered and frozen for up to 2 weeks.