Preheat and prep: Set your oven to 400°F (200°C). Lightly grease a 9x13-inch baking dish. Pat the chicken dry with paper towels for better browning and texture.

Season the chicken: In a bowl, toss chicken with olive oil, salt, pepper, Italian seasoning, and onion powder. Make sure each piece is evenly coated.

Quick sear (optional but recommended): Heat a skillet over medium-high. Sear chicken 1–2 minutes per side to get a little color. Transfer to the baking dish. If skipping this step, place seasoned chicken directly in the dish.

Make the sauce base: In a medium bowl, whisk together pesto, heavy cream, softened cream cheese, minced garlic, and lemon zest (if using). It should be smooth and spoonable. If too thick, add a splash more cream.

Assemble the bake: Pour the creamy pesto sauce over the chicken and gently spread to cover. Sprinkle shredded mozzarella and grated Parmesan evenly on top.

Bake: Place the dish in the oven and bake for 20–25 minutes for thighs (25–30 for thicker breasts), until the chicken reaches an internal temperature of 165°F (74°C) and the sauce is bubbling.

Broil for color: Turn the broiler on high for 1–2 minutes to brown the cheese slightly. Watch closely to avoid burning.

Rest and garnish: Let the bake rest for 5 minutes so the sauce settles. Top with torn fresh basil and a pinch of red pepper flakes if you like a little heat.

Serve: Spoon extra sauce over the chicken. Pair with zucchini noodles, roasted broccoli, cauliflower mash, or a crisp green salad.