In a large pot of boiling water, cook penne pasta until al dente, according to package directions. Drain.
Season chicken pieces with ranch seasoning. Spray a large non-stick skillet with cooking spray.
Cook chicken in prepared skillet over medium-high heat until no longer pink in center; about 10 to 12 minutes. Remove chicken from skillet and onto a large plate. Tent with foil to keep warm. Carefully wipe skillet clean so you can cook sauce in it.
Add butter to skillet and melt it over medium heat. Once melted, add garlic and stir until fragrant; about 1 minute. Whisk in ranch seasoning and flour. Cook for 30 seconds whisking constantly. Slowly whisk in heavy whipping cream. Continue to cook and stir for one minute or until mixture starts to boil. Remove from heat and stir in Parmesan cheese until it completely melts. Season sauce with pepper.
Add drained cooked pasta and cooked chicken to ranch sauce in skillet. Stir to combine.
Pour this mixture into a greased 9x13 inch baking pan. Top with Mozzarella cheese and chopped bacon. Bake in a preheated 375 degree F. oven, uncovered, for 20 minutes or until cheese is melted and bubbling.
Remove from oven and let rest/cool 5 to 10 minutes before serving. Serve with chopped fresh parsley, if desired. Enjoy!