Preheat an oven to 375°F.
Butter or spread olive oil in a 9-by-13-inch baking dish.
Bring a large pot of salted water to a boil over high heat.
Add a splash of olive oil (optional that I enjoy adding, but it is entirely up to you).
Add pasta and cook [b]until not quite al dente[/b], about 2 minutes less than the package instructions.
Stir occasionally during this time.
Drain and transfer to a large bowl.
While the pasta is still warm, drizzle with the truffle oil or add the truffle butter and stir well.
Place large saucepan on the stove on medium-high heat and melt the 4 Tbs. butter.
Whisk in the cream.
Simmer, whisking frequently for about 5 minutes.
Remove from the heat.
Add the cheeses one at a time with a good stir until smooth after each addition (off of the stove heat).
Add the minced garlic.
Pour the cheese sauce onto the pasta.
Add the minced prosciutto or pancetta
OPTIONAL: If adding sautéed porcini mushrooms, this is the point to add them.
Transfer the pasta and cheese mixture to the prepared baking dish.
In a small bowl, mix the minced chives/Italian parsley with Italian-flavored Panko crumbs.
Stir well.
Sprinkle the herb-flavored crumbs all over the pasta and cheese mixture.
Bake until the top is lightly browned and the sauce is bubbly, 35 to 45 minutes.
Remove from the oven and let stand for 5 minutes.
Drizzle pasta and cheese mixture with a little more truffle oil.
Broil for 2 minutes longer or until golden brown.