In a medium skillet, heat the EVOO, 1 turn of the pan, over medium-high heat. Cook the sausage, breaking it up into little bits with a wooden spoon, until browned. Drain off all but a few tablespoons of fat from the sausage. Reduce the heat to medium, push the sausage to the sides of the pan, add the onion and garlic to the center and cook until tender, 6 to 8 minutes. Mix into the sausage and remove the pan from the heat.
Preheat the broiler with the rack set 8 to 10 inches away from the heat. Combine the cream cheese with half the scamorza and half the Parmigiano-Reggiano. Stir in the oregano and then fold the sausage into the combined cheeses. Spread the mixture into a casserole. Top with the tomato sauce and the remaining cheese. Cover with foil and broil for 2 minutes, then uncover and broil until bubbling, about 5 minutes. Serve with the semolina bread.