Bring a large pot of well-salted water to a boil. Cook the pasta according to the package directions until al dente. Reserve at least 1/2 cup of pasta water, then drain.

While the pasta cooks, melt the butter in a large skillet over medium heat. Add the diced ham and cook for 2 to 3 minutes, until heated through and lightly browned.

Add the minced garlic and cook for about 30 seconds, just until fragrant. Pour in the heavy cream, bring it to a gentle simmer, and cook for 2 to 4 minutes without allowing it to boil vigorously.

Stir in the frozen peas and heat for 1 to 2 minutes. Reduce the heat to low or remove the skillet from the burner, then add the Parmesan, salt, pepper, and optional nutmeg.

Stir until the sauce is smooth, add the drained pasta, and toss to coat. Add reserved pasta water a tablespoon or two at a time until the sauce is creamy and clings to the pasta. Taste, adjust seasoning, and garnish with parsley and additional Parmesan if desired.