Carefully clean the artichokes and brown them in a pan with the garlic and a little oil, add salt and pepper and cook. In the meantime, boil the potatoes in salted boiling water. Crush the potatoes and blend the artichokes until you get a puree. In a bowl mix the artichokes, the potatoes, the whipped mozzarella, the parmesan, the minced pistachios. Cook the paccheri in abundant salted water, drain them al dente and put them to drain on a cloth. Meanwhile blend the other mozzarella (do not need to drain) and add a lot of cream as needed to get a smooth cream. Take a ceramic plate and lay the cream of buffalo on the bottom, helping you with a pastry rings. With a pastry bag, fill the paccheri with the mousse, place them over the cream, pour a little oil and put them in a hot oven at 160 ° for 2-3 minutes (or just enough time to heat the pasta and the cream) . Remove from the oven sprinkle with pistachios and serve.