In saucepan combine 1 1/2 pounds Italian Blend Cheese and water. Cook over low heat, stirring occasionally, until cheese is melted. Cook pasta according to package directions, drain.
Toss peppers and onion with olive oil, salt and pepper. Roast at 425°F until beginning to brown but still remain bright in color.
Combine cheese sauce, pasta, sausage and roasted vegetables. Turn into a half hotel pan that has been sprayed with nonstick cooking spray. Bake, covered, at 350°F for 30 minutes. Uncover, top with remaining 4 ounces cheese. Bake for an additional 5 to 10 minutes until cheese is melted.