Baked Rigatoni with Bechamel Sauce

1 stick unsalted butter (4 ounces)
1/2 cup plus 2 tablespoons flour
1 quart whole milk, room temperature
Pinch fresh nutmeg
Sea salt and white pepper
1 cup grated fontina
1/2 pound thinly sliced proscuitto, julienned
1 pound dry rigatoni
3 tablespoons unsalted butter, diced

Preheat oven to 425°.

Sauce:
In a 2 quart saucepan, melt the butter over medium heat. Add the flour and whisk until smooth, about 2 minutes. Always stirring, gradually add the milk and continue to whisk until the sauce is smooth and creamy. Simmer until it is thick enough to coat the back of a spoon. This will take approximately 10 minutes. Remove from heat and stir in nutmeg, 1/2 cup fontina, proscuitto, and season with salt and pepper. Set aside.

In a large pot, bring to boil 6 quarts of salted water. Add the rigatoni and cook for about 5 minutes. The insides should still be hard. Drain in a colander. Return pasta to the pot and pour in béchamel sauce. Using a wooden spoon, mix well until all the pasta is coated with the sauce.

In a greased 13 x 9 baking dish, pour the pasta with cream sauce. Smooth out top and sprinkle with the remaining 1/2 cup fontina. Dot the top with butter and bake in oven for 25 minutes or until bubbling and the top is golden brown.