Mix the roasted, chopped pistachios, chopped parsley, warm butter, pepper, and garlic. Spread the stuffing on the meat leaving an edge distance of approx. 2 cm. Then wrap the pork tightly creating a roulade and tie with a kitchen thread. Heat the oil in a pan and fry the pork rolaude on all sides. Remove from the fire and set aside. Put the roulade in an ovenproof dish. Put in the oven for 40-50 minutes. In the meantime, pour the fat over the roulade until the roulade is moist. Remove the kitchen thread before serving. Cut the roulade in slices.