Prepare the cheese mixture: Finely grate the Parmesan and whisk it together with the cornstarch. Set aside.
Cook the pasta: Boil the macaroni in salted water for 1 minute less than the package directions. Drain and let it cool for about 10 minutes.
Reduce the wine: While the pasta cooks, boil the white wine over high heat for 5–6 minutes, until reduced to about 2 tablespoons and slightly syrupy.
Make the sauce: Add the chicken stock to the reduced wine and lower the heat. Whisk in the Parmesan-cornstarch mixture for about 1 minute until smooth. Turn off the heat.
Combine: Toss the drained macaroni with truffle oil. Fold in the cheese sauce and softened cream cheese until creamy and glossy.
Bake: Transfer to a small or medium baking dish. Sprinkle with extra Parmesan and broil at 240°C (465°F) for 4–5 minutes, until golden brown.
Rest and serve: Let the mac and cheese rest for 5 minutes before serving.