Prepare the macaroni and cheese base by bringing a large pot of salted water to boil; add the pasta and cook until al dente, according to package directions, about 10 minutes.
Meanwhile, heat a medium saucepan, over medium high heat, and saute shallots, in the olive oil, until they just begin to color; stir in heavy cream, reduce heat to a simmer, and cook until reduced by half, about 8 to 10 minutes.
Whisk in cheese until melted; stir in drained pasta.
Remove from heat and keep warm.
Drizzle the olive oil over the chicken and season with salt and pepper; sprinkle with parsley and rosemary.
Grill chicken, over medium heat, to an internal temperature of 165 degrees F; remove from heat, cover, and keep warm.
In a medium sized skillet, over medium high heat, cook pancetta until crisp, about 5 to 7 minutes; remove pancetta with a slotted spoon and set aside (leave fat in pan).
Sprinkle the bread crumbs into the pan and stir, until toasted, about 1 minute; remove from heat and drain bread crumbs on paper toweling.
Heat the macaroni base, over medium heat, until hot, stirring frequently.
Meanwhile, slice the chicken into strips; stir the chicken into the macaroni base, then stir in the pancetta, chopped parsley and white truffle oil; toss to coat.
Divide mac 'n cheese among 4 serving bowls, top with bread crumbs, and serve.