01 - Whisk together buttermilk, mayonnaise, ranch seasoning, minced garlic, olive oil, dried parsley, black pepper, paprika, and salt in a large bowl until smooth and well combined.
02 - Add chicken cubes to the marinade, tossing thoroughly to coat each piece evenly. Cover bowl 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 to prevent burning during grilling.
04 - Thread marinated chicken pieces onto skewers, leaving a small space between each cube to ensure even cooking and proper heat circulation.
05 - Lightly oil 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 grill lid to allow cheese to melt and become slightly golden.
07 - Remove skewers from grill and transfer to serving platter. Garnish with chopped fresh parsley if desired. Serve immediately while hot.