Prepare the macaroni in a large saucepan according to the directions on the package. Drain and return to the saucepan to keep warm.
Heat the oven to 350 degrees F.
In a small saucepan over medium heat, melt the butter add the onion and chopped green bell pepper and cook for 5 minutes, stirring occasionally, until crisp tender. Remove from the heat; add vegetables to the macaroni in the saucepan along with the cheese spread, shredded cheese and hot red pepper sauce, if desired. Toss until well mixed.
Spoon the mixture into a 2 1/2-quart casserole and bake 30 minutes or until hot and bubbly. Garnish with pepper rings and parsley sprigs if desired.