01 - In a large mixing bowl, combine the olive oil, gluten-free soy sauce, lime juice, minced garlic, ground cumin, smoked paprika, dried oregano, black pepper, kosher salt, and chili powder. Whisk thoroughly until all spices are evenly incorporated into a smooth paste.
02 - Pat the butterflied chicken completely dry with paper towels. Rub the marinade generously over every surface of the chicken, working it carefully under the skin to ensure deep flavor penetration. Cover tightly and refrigerate for at least 2 hours, though overnight yields the most flavorful results.
03 - Preheat the oven to 425°F. Line a roasting pan with aluminum foil and set a wire rack inside. Place the marinated chicken skin-side up on the rack, allowing air to circulate underneath for even crisping.
04 - Roast the chicken for 45 to 55 minutes, or until the skin turns deeply golden and crispy. Insert a kitchen thermometer into the thickest part of the thigh without touching bone; it should register 165°F. Remove from the oven and allow the chicken to rest for 10 minutes before carving to let the juices redistribute.
05 - While the chicken rests, combine the cilantro leaves, seeded jalapeño or serrano chile, garlic cloves, mayonnaise, sour cream, lime juice, grated Parmesan cheese, and olive oil in a blender or food processor. Blend on high until completely smooth and vibrant green. Season with salt and pepper to taste, adjusting the heat level as desired.
06 - Carve the rested chicken into serving portions and arrange on a platter. Drizzle generously with the Aji Verde sauce, passing additional sauce at the table. Pair with roasted potatoes or a simple fresh salad for an authentic presentation.