Preheat oven to 425 degrees F. Spray 9-inch pie plate with cooking spray; set aside. Stir together mac and cheese and bacon in medium bowl; set aside.
Unroll pizza dough; press into a 15x9 rectangle. Cut into 24 square pieces. Divide mac and cheese mixture evenly and place in the center of each piece. Pull edges of each piece of dough up and around mac and cheese mixture to enclose completely; pinching seams to seal. Place seam-side down in pie plate.
Brush tops of dough with butter. Sprinkle evenly with parsley flakes and garlic powder. Bake 15 to 20 minutes or until top is golden brown. Serve bombs with ranch dressing.