01 - In a large mixing bowl, whisk together the olive oil, soy sauce, lime juice, minced garlic, ground cumin, smoked paprika, dried oregano, black pepper, kosher salt, and chili powder until a smooth, fragrant paste forms.
02 - Pat the butterflied chicken thoroughly dry with paper towels. Rub the marinade generously over the entire surface and carefully under the skin to ensure deep flavor penetration. Cover tightly and refrigerate for at least 2 hours, preferably overnight for optimal results.
03 - Preheat the oven to 425°F. Line a baking tray with aluminum foil and set a roasting rack on top. Place the marinated chicken skin-side up on the rack, allowing even heat circulation around the bird.
04 - Roast the chicken for 45 to 55 minutes, or until the skin turns deeply golden and crisp. Insert a kitchen thermometer into the thickest part of the thigh — it should register 165°F. Remove from the oven and let the chicken rest for 10 minutes before carving to allow the juices to redistribute.
05 - While the chicken rests, combine the cilantro leaves, jalapeño or serrano chile, garlic cloves, mayonnaise, sour cream, lime juice, Parmesan cheese, and olive oil in a blender or food processor. Blend on high until completely smooth and creamy. Season with salt and pepper to taste.
06 - Carve the rested chicken into serving portions and arrange on a platter. Drizzle generously with the aji verde sauce and serve immediately alongside roasted potatoes or a fresh salad.