Preheat oven to 350° F. Cook
macaroni according to directions—but do not add salt to the cooking water. Drain and
set aside.
Heat the olive oil in a large
saucepan over medium heat. Add onions to the saucepan and sauté for about 3 minutes.
Remove from the heat and add the
cooked macaroni, along with the rest of the ingredients to the saucepan and mix
thoroughly.
Spray a casserole dish with
nonstick cooking spray. Transfer macaroni mixture into casserole dish. Bake for 25
minutes or until bubbly. Let stand 10 minutes before serving.