1. Heat the three cheese gourmet macaroni according to package directions.
2. Meanwhile, sauté the onion and mushrooms for 7–8 minutes over medium-high heat.
3. In another frying pan, sweat the pancetta for 5 minutes.
4. Stir the mac&cheese, onion, mushrooms and pancetta in a baking dish. Sprinkle with breadcrumbs.
5. Place under the grill for a few minutes, until the surface becomes crispy and golden. Sprinkle with green onions and serve.