Bring a large pot of water to a boil and boil pistachios for 2 to 3 minutes. Drain and remove the skin from the pistachios by rubbing them inside a clean and dry cloth. Spread out on another clean cloth and let them dry completely, about 1 hour. Grind pistachios in a blender or using a mortar and pestle until they form a paste. Set aside.
Pour milk into a saucepan over medium heat and bring to a simmer. Remove from heat and set aside to cool slightly.
Combine eggs and sugar in a bowl and beat using an electric mixer until pale and fluffy, about 5 minutes. Pour into the saucepan with the milk and stir well. Return the pan to low heat and cook until just simmering. Remove from heat and transfer to a bowl to stop the cooking process. Stir in orange blossom water.
Transfer ground pistachios to a bowl, add egg-milk mixture, and stir well to combine. Set aside.
Beat cream in a chilled glass or metal bowl using an electric mixer until soft peaks form. Gently fold pistachio mixture into the bowl with the cream.
Pour mixture into an ice cream maker and freeze according to manufacturer's instructions, about 20 minutes. Transfer to an airtight container and freeze until firm, about 4 hours.
