Roll out the pastry on a lightly floured surface into a 12-inch circle, about 1/4-inch thick. Carefully roll the dough up onto the pin (this may take a little practice) and lay it inside a 9-inch tart pan with a removable bottom. Press the dough into the pan so it fits tightly. Shave off the excess hanging dough with a knife. Put the tart in the refrigerator.

Preheat the oven to 350 degrees F.

Line the tart with aluminum foil and add dried beans to keep the sides of the tart from buckling. Bake for 30 minutes, then remove the foil and weights and remove from the oven. Remember the tart will be cooked again with the filling. It should be cooked but light in colour so that it will not burn on the second bake. Set aside to cool and lower the oven temperature to 325 degrees F.

To make the filling: Heat the heavy cream and milk in a pot over medium-low flame, until it simmers slightly around the edges. Remove from the heat; add the chopped chocolate, Add the sugar and salt and whisk until well incorporated. Beat the eggs in a small bowl and add them to the chocolate mixture, stir until completely blended. Pour the filling into the cooled tart shell and bake for 15 to 20 minutes until the filling is set and the surface is glossy. Cool before cutting. Add pistachios.