01 - Combine chili peppers, garlic, onion, lemon juice, apple cider vinegar, olive oil, smoked paprika, oregano, salt, black pepper, and brown sugar in a blender or food processor. Blend until a smooth, vibrant paste forms.
02 - Place chicken thighs and drumsticks in a large bowl or resealable plastic bag. Pour the marinade over the chicken, massaging it into every piece to ensure thorough, even coating. Cover tightly and refrigerate for at least 2 hours—overnight yields the deepest flavor penetration.
03 - Preheat the oven to 400°F or prepare a grill for medium-high heat, ensuring the grate is well-oiled to prevent sticking.
04 - Remove chicken from the marinade, allowing excess to drip off. Reserve a small amount of marinade for basting during cooking. Arrange the pieces on a foil-lined baking sheet or directly onto the preheated grill grate, skin-side up.
05 - Cook for 35 to 40 minutes, turning and basting once or twice with the reserved marinade. The chicken is done when the internal temperature reaches 165°F, the skin is deeply golden and crispy, and the edges show a desirable light char.
06 - Transfer the chicken to a platter and rest for 5 minutes to allow juices to redistribute. Garnish generously with chopped fresh cilantro or parsley and serve alongside lemon wedges for squeezing.