Preheat oven to 350 degrees. Cook bacon in a large skillet over medium heat until crisp. Set bacon aside. Remove all grease from pan except 2 tablespoons. Add onion (if using) and saute for a few minutes. Whisk in flour until a thick paste forms. Stir in chicken broth, half and half and dijon mustard. Stir until mixture slightly thickens, then add in parmesan cheese. Stir until cheese is melted. Remove from heat.

Spray a 8×8 baking dish with non-stick spray. Layer rice, chicken and then broccoli in the dish. Pour cheese sauce evenly over the broccoli. Crumble bacon evenly on top. Bake for 15 minutes or until heated through. Serve!