Put together into a saucepan eight egg yolks, half a pound of powdered sugar, a piece of vanilla-bean one inch long and split in two, also a pint of sweet cream, and six ounces of finely grated cocoa. Mix well with the spatula for two minutes, then place the pan on the hot stove, and stir constantly while heating, but under no circumstances must it boil. Remove it from the fire, and lay the pan in a cool place on the table for thirty minutes. Put an ice-cream freezer into a tub, fill it all round with broken ice mixed with rock-salt, remove the cover, and after wiping the freezer well, strain the preparation through a sieve into it, cover it again, and with the hands turn the handle of the cover for five minutes in opposite directions. Lift up the cover, and with the spatula detach the preparation that adheres to the sides, readjust the cover, and turn again the handle, beginning in an opposite direction from the first time ; after five minutes, detach from the sides as before, and repeat for the third time the turning process. Finally lift off the cover, and detach the cream from all around, and it will now be thoroughly firm, so cover it again, and let it rest. Beat up to a froth one gill of sweet cream as for No. 1254 ; take a glass or silver stand, and with an ice-cream spoon remove the cream from the freezer, spoonful by spoonful, and dress it in the centre of the bowl, keeping it as high as possible, and giving it a pretty, pyramid shape. Fill a paper cornet with the whipped cream, cut off the point, and decorate artistically the top and sides of the plombiere. Chop up very fine two ounces of pistache, and sprinkle them evenly over the surface, then send to the table.