Combine the chopped parsley, minced garlic, red wine vinegar, olive oil, red pepper flakes, and salt in a mixing bowl. Whisk everything together until the sauce is well blended and slightly emulsified, filling your kitchen with a fresh herbal aroma.
Use a brush or spoon to generously coat the chicken with half of the chimichurri sauce, making sure every piece is covered with the vibrant green marinade. Let the chicken sit for at least 10 minutes to absorb the flavors.
Preheat your grill or grill pan over medium-high heat until hot, with a slight smoky smell filling the air. Place the marinated chicken on the grill, listening for a gentle sizzle as it hits the hot surface.
Grill the chicken for about 6-8 minutes per side, or until the meat is golden brown and has visible grill marks. Baste or brush with the remaining chimichurri for extra flavor, allowing the sauce to char slightly and caramelize.
Use tongs to flip the chicken and check for the firm, slightly springy texture that indicates it's cooked through. The exterior should be crispy and smoky, while the interior remains juicy.
Once cooked, transfer the chicken to a serving platter and let it rest for a few minutes to lock in the juices. Spoon the remaining fresh chimichurri over the top for a bright, herbaceous finish.
Serve the grilled chimichurri chicken hot, garnished with additional parsley if desired, and enjoy the juicy, crispy, and flavorful dish that captures the essence of fresh herbs and smoky grilling.
