Prepare pasta according to package directions. Meanwhile, in a very large skillet cook mushrooms and pepperoni in margarine over medium heat for 5 minutes or until mushrooms are just tender. Drain fat. Stir in spinach. Cook and stir for 1 minute or until spinach begins to wilt. Remove from heat.
Drain cooked pasta. In a large bowl combine pasta, pepperoni mixture, 3 tablespoons of the Parmesan cheese, the basil, and lemon juice. Toss to combine. Sprinkle with remaining Parmesan cheese. If desired, serve with breadsticks. Makes 4 servings.