In a large mixing bowl, melt the unsalted butter and let it cool slightly. Add minced garlic, smoked paprika, chili powder, ground cumin, dried oregano, cayenne pepper, salt, black pepper, and fresh lemon juice. Whisk together until smooth.

Add the boneless, skinless chicken to the marinade, ensuring each piece is coated. Cover with plastic wrap and refrigerate for 1 to 4 hours.

Preheat your grill or grill pan to medium-high heat (about 400°F/200°C).

Once marinated, take the chicken out and thread onto skewers, ensuring not to overcrowd them.

Cook the skewers on the preheated grill for about 4 to 5 minutes on each side, or until the internal temperature reaches 165°F (75°C).

Once grilled, brush with leftover marinade or melted butter and let them rest for a few minutes before serving, sprinkled with fresh parsley.