Preheat oven to 425. In a mixing bowl: mix ranch, butter & salt/pepper. Cut aluminum foil into 4 squares, coat with cooking spray. Place potatoes in a bowl, and coat with 4tbs of ranch mixture, coat evenly. Place chicken on foil, coat with s&p. Divide potatoes evenly betwwen the portions, add onion if desired. Drizzle rest of butter mixture over chicken.

Fold aluminum foil over chicken/potatoes to make a "packet." Bake for 45 minutes. Open packet & sprinkle cheese & bacon over chicken, cook for 2-4 minutes.

Note: can also be done on a medium high grill for 30 min & 2 min for cheese!