In a medium nonreactive saucepan, toss the apples with the Lemon zest, adding the sugar if you like slightly sweeter apples. Cover and cook over medium heat for 10 minutes, or until the apples give up some of their juice, but keep their shape. Shake the pan from time to time to prevent sticking. Set aside.

In a large skillet, melt 4 tablespoons of the butter and heat the oil over medium-high heat. Add the onions and sauté until crisp and golden brown, about 10 minutes. While the onions are cooking, cook the macaroni in a large kettle of lightly salted boiling water until just tender, about 10 to 12 minutes.

Drain the macaroni. Add the remaining butter, the cheese, salt, and pepper and toss all together until the cheese melts. Spoon into 4 warm soup plates and top with onions. Sprinkle with the chives and serve with the stewed apples on the side.