Prepare pasta according to directions on package. In a heavy saucepan melt 2 tablespoons of the butter over medium heat. Add the flour and stir with a wooden spoon until well blended, about 2 minutes. Stirring constantly, gradually add the milk. Continue to stir until it thickens and is smooth and creamy, about 5 minutes. Add the ham, about half of the Parmesan and 6 tablespoons butter. Season with nutmeg and salt and pepper to taste. Continue stirring until the butter melts. Grease a 9×13 pan. Drain the pasta and transfer it to the prepared dish. Pour the white sauce over the top and toss well. Sprinkle evenly with the remaining Parmesan cheese. Place the dish under the broiler until the top is golden, about 3 minutes. Serve at once.