First grind 3/4 of the pistachio nuts together with the sugar in a chopper very finely. Put the milk, double cream, honey and orange blossom water in a saucepan, add the pistachio-sugar mixture and simmer gently over low to medium heat, stirring frequently. As soon as the mixture has boiled down by a quarter, remove the saucepan from the heat and let everything cool down. Then coarsely chop the remaining pistachio nuts, rub off the peel of the orange, add both together with the condensed milk to the cream mixture and stir everything well. Cover the pot with cling film and let it cool in the refrigerator for at least 2 hours. Then put the mixture in the ice cream maker and let it freeze according to the manufacturer's instructions. If the ice cream is still too creamy, pour it into a shallow bowl, close it and put it in the freezer for 1-2 hours.