01 - Whisk together buttermilk, mayonnaise, ranch seasoning, minced garlic, olive oil, dried parsley, black pepper, paprika, and salt in a large bowl until smooth.
02 - Add chicken cubes to the marinade, toss to coat evenly. Cover and refrigerate for at least 30 minutes, 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 use.
04 - Thread marinated chicken pieces onto skewers, leaving a small space between each piece for 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 is cooked through and has distinct grill marks.
06 - During the last 2 minutes of grilling, sprinkle Parmesan cheese generously over the skewers. Close the grill lid to help the cheese melt.
07 - Remove skewers from the grill. Garnish with chopped fresh parsley if desired and serve immediately while hot.