01 - Whisk together buttermilk, mayonnaise, ranch seasoning, minced garlic, olive oil, dried parsley, black pepper, paprika, and salt in a large bowl until fully combined.
02 - Add chicken cubes to the marinade, tossing to coat evenly. Cover and refrigerate for at least 30 minutes, or up to 2 hours for deeper flavor penetration.
03 - Preheat grill or grill pan to medium-high heat. If using wooden skewers, soak them in water for 30 minutes prior to threading.
04 - Thread marinated chicken pieces onto skewers, leaving small gaps between pieces to ensure even cooking.
05 - Lightly oil the grill grates. Place skewers on the grill and cook for 5–7 minutes per side, turning once, until chicken reaches internal temperature of 165°F and develops distinct grill marks.
06 - During the final 2 minutes of grilling, sprinkle Parmesan cheese generously over each skewer. Close the grill lid to allow cheese to melt and slightly crust.
07 - Remove skewers from grill and transfer to serving platter. Garnish with chopped fresh parsley if desired. Serve immediately while hot.