Preheat oven to 350°F and butter a 2 quart baking dish. Bring a large pot of salted water to a boil, and cook the pasta to very al dente. Drain and set aside.
Meanwhile, crisp prosciutto by heating a large heavy bottomed dutch oven or pot over medium heat. Add prosciutto and cook until crisp. Remove from pot with a slotted spoon and set aside.
To the same pot, add 4 tablespoons of the butter and melt over medium low heat. When butter is melted, add garlic and flour and cook, stirring for about 2 minutes or until golden brown.
Slowly whisk in milk and mix until it is all incorporated. Switch to a wooden spoon and cook over medium heat, stirring constantly, until the sauce thickens and coats the back of a spoon. Season with salt, pepper, cayenne, nutmeg, and dijon. Remove from heat and add the shredded BelGioioso Parmesan and the BelGioioso Fresh Mozzarella. Stir until melted. Add pasta and reserved prosciutto and fold until well combined.
Add the macaroni and cheese to the buttered baking dish. Melt remaining butter in a small frying pan and add panko and thyme. Cook until the breadcrumbs begin to brown and the thyme smells fragrant. Season with a pinch of salt. Add breadcrumb mixture to the top of the mac and cheese, then top with BelGioioso Parmesan flakes and bake for about 45 minutes or until golden brown and bubbly.