Marinate the Chicken: In a blender, combine cilantro, lemon zest and juice, lime juice, olive oil, oregano, paprika, garlic powder, onion powder, black pepper, herb-seasoning blend, and Creole seasoning. Blend until smooth to create a thick, aromatic marinade. Rinse and pat the chicken thighs dry, then place in a large dish or freezer bag and coat thoroughly on all sides. Lift the skin gently to spread the marinade underneath for deeper flavor. Cover and refrigerate for at least 3 hours, or ideally overnight.
Roast the Chicken: Preheat the oven to 350°F and lightly grease a baking dish or roasting pan. Remove the chicken from the refrigerator and allow it to come to room temperature for 15–20 minutes. Arrange the chicken thighs in a single layer, skin-side up. Roast for 40–50 minutes, or until the juices run clear and the internal temperature reaches 165°F. During the last 20 minutes, baste the chicken with its pan juices for added moisture and flavor. For crispy, golden skin, broil for 5 minutes at the end of cooking.
Make the Mashed Potatoes: While the chicken bakes, place the peeled and cut potatoes in a large pot of salted water. Bring to a boil and cook for 15–20 minutes, or until tender when pierced with a fork. Drain well and return to the pot. Add butter, heavy cream, Creole seasoning, garlic powder, onion powder, and black pepper. Mash until smooth and creamy, adjusting seasoning to taste. Keep warm.
Prepare the Cream Gravy: In a saucepan, heat olive oil and butter over medium heat. Whisk in flour and cook for about 1 minute to form a light roux. Gradually add broth while whisking continuously to avoid lumps. Once the mixture begins to thicken, stir in heavy cream, black pepper, garlic powder, onion powder, and Creole seasoning. Add a small dash of hot sauce if desired for extra depth. Simmer for 5–7 minutes until smooth and creamy.
Serve: Plate the roasted chicken with a generous serving of mashed potatoes. Drizzle warm cream gravy over both and garnish with a sprinkle of fresh cilantro or parsley. Serve immediately and enjoy this cozy, flavor-packed meal.