In a saucepan, heat the butter over medium heat. Add the flour and with a whisk, stir until bubbling, 2 minutes. Add the milk and whisk together. Stir the mixture with a wooden spoon until it thickens. Add the Fontina, Gorgonzola, Pecorino Romano and Mozzarella and stir until the cheese melts. Season with salt & pepper. Remove from the heat and set aside.
Pre-heat oven to 375 F.
Bring a large pot of salted water to a boil. Add the pasta and cook until al dente. Drain and toss with the cheese sauce. Transfer the pasta and sauce to a lightly oiled baking dish. Sprinkle with bread crumbs. Bake in the oven until the top is golden and the sauce is bubbling, about 30 minutes.