Prepare the Green Goddess marinade: In a food processor or blender, combine the Greek yogurt, fresh parsley, chives, dill, lemon juice, garlic cloves, anchovy fillets (if using), and 30ml (2 tbsp) of olive oil. Blend until smooth and creamy. Season with salt and black pepper to taste. You should have approximately 250ml (1 cup) of dressing.

Marinate the chicken: Place the chicken thighs in a large bowl or a resealable plastic bag. Pour about two-thirds of the Green Goddess dressing over the chicken, ensuring each piece is well coated. Reserve the remaining one-third of the dressing for serving. Cover the bowl or seal the bag and refrigerate for at least 30 minutes, or up to 4 hours, to allow the flavors to meld.

Preheat your grill: Preheat your grill to medium-high heat, around 200°C (400°F). If using a grill pan, heat it over medium-high heat on the stovetop.

Grill the chicken: Remove the chicken thighs from the marinade, letting any excess drip off. Discard the marinade. Place the chicken thighs on the preheated grill. Grill for 6-8 minutes per side, or until the chicken is cooked through and has reached an internal temperature of 74°C (165°F). The exact time will depend on the thickness of the thighs and the heat of your grill.

Rest and serve: Once cooked, remove the chicken from the grill and let it rest for 5 minutes. Serve the Green Goddess Grilled Chicken Thighs warm, drizzled with the reserved Green Goddess dressing.