COOK pasta in large saucepan as directed on package, omitting salt and adding spinach, peppers and mushrooms to saucepan for the last 3 min.
MEANWHILE, cook cream cheese product and milk in same saucepan on low heat until cream cheese is completely melted and sauce is well blended, stirring frequently.
DRAIN pasta; place in large bowl. Add cream cheese sauce; toss to coat. Top with basil and grated cheese.