In a medium saucepan, heat the milk over medium heat until small bubbles form around the edges. In a larger saucepan, melt the butter over medium-low heat. Add the flour and stir well. Continue to cook, stirring, until thick and smooth, about 2 minutes. Slowly begin adding the hot milk to the large saucepan, whisking constantly while adding. The sauce will start out lumpy and become smooth as the milk is incorporated. Stir in the nutmeg and freshly ground pepper. Turn the heat up to medium and bring the sauce to a simmer for an additional 2 minutes. Remove from heat and set aside while you prepare the pasta.
Preheat the oven to 350 degrees F. Butter a shallow 2½-quart baking dish.
ASSEMBLE THE DISH:
In a large bowl, toss the cooked pasta with the sauce. Stir in the peas, ham, provolone and ¾ cup of the Parmesan. Scrape the mixture into the baking dish and sprinkle with the remaining Parmesan.
Cover the baking dish with aluminum foil. Bake for 25 minutes. Uncover and bake until the sauce is bubbling around the edges and the center is hot (about 10 minutes more). Remove from the oven and let cool for about 10 minutes before serving.
Notes
If you are making this recipe as "egg free," just make sure the pasta and ham don't have any egg products in them.