Cook pasta as directed on package, omitting salt and adding broccoli to the boiling water for the last 4 min.
Meanwhile, cook bacon in large skillet until crisp. Remove bacon from skillet, reserving 3 Tbsp. drippings in skillet. Drain bacon on paper towels. Add onions to reserved drippings; cook on medium heat 4 to 5 min. or until tender. Add flour; whisk, scraping browned bits until blended. Gradually stir in milk. Bring to boil, stirring constantly; cook and stir 2 min. or until thickened.
Add Neufchatel, blue cheese and pepper; stir until cheese is melted. Remove from heat. Stir in 1 Tbsp. Parmesan.
Drain pasta mixture; place in serving bowl. Add sauce; toss lightly. Crumble bacon; sprinkle over pasta with remaining Parmesan.