For the Pistachios

1. Bring a medium sized pot of water to a boil and add the shelled pistachios. Let them boil for 4 minutes then drain them and place them on a clean kitchen towel.
2. Fold the towel over and rub the pistachios in the towel to loosen the skins. Separate the pistachios from the skins and discard the skins.
3. Add the pistachios to a food processor (or high power blender) with only ¼ cup (60ml) of the milk. Keep pulsing on high on and off for 5 minutes until the pistachios turn into a smooth paste. Stop the food processor 3-4 times to scrape down the sides. 
4.  Leave pistachio mixture in the blender. Cover and set aside. Start making the cream. 

For the Cream

1. In a medium mixing bowl whip the egg yolks, sugar, and cornstarch with an electric mixer until light and foamy, about 5 minutes. Set aside.
2.  Add the egg and cornstarch mixture to the blender with the pistachio cream. Mix until combined and smooth- this is your pistachio mixture. Set aside. 
3.  In a sauce pan heat the milk. Turn heat to medium and warm milk until a soft boil (little bubbles on the sides and steam starts to form).
4. When the milk is hot, remove from heat. Using a whisk- start adding the pistachio mixture, a little at a time into the milk. It’s very important to stir constantly until you achieve a unified mixture.
5. Put the saucepan back on low heat and continue whisking. Simmer for about 3-4 minutes until the cream begins to thicken. It’s very important that the cream NEVER BOILS. In this way you have a smooth cream without lumps and without chunks of cooked egg.
6. If you have a cooking thermometer you can check that the temperature never exceeds 85°C (185 F). Otherwise, as soon as you see that bubbles begin to form in the cream, lower the heat. You can even remove it from the heat for a few seconds and put it back. 
7. Keep cooking on low medium heat until cream is thickened. When the cream is well thickened (it will stick to the back of a spoon and not drip off), remove from heat and add vanilla extract. Immediately pour it into a cold glass container. Important to remove the pistachio cream immediately from hot saucepan to prevent it from cooking longer.
8. While cooling, cover the cream with plastic wrap. Keep it in contact with the cream. This step is to avoid forming a skin on the cream surface. Refrigerate at least 3 hours for it to set.