In a saucepan bring to a boil milk and cream, remove from heat and add the panna cotta mixture, mix well with a whisk and leave to stand for 2-3 minutes. Add the pistachio cream to the panna cotta, put the mixture in molds and place them in the refrigerator for at least 4/6 hours. In a pan melt the sugar, add the pistachios and cook over high heat for a few minutes. Once caramelized, arrange them on a baking sheet and let them cool. Turn out the panna cotta in the middle of a plate, decorate with the crumbled pistachios and the pistachio topping and serve.