Prep the oven and pan. Heat the oven to 400°F (200°C). Lightly grease a 9x13-inch baking dish with olive oil or cooking spray.

Season the chicken. Pat the chicken dry and place it in the baking dish. Drizzle with olive oil, then sprinkle with 1/2 teaspoon salt, 1/4 teaspoon pepper, and the onion powder. Spread evenly so each piece is seasoned.

Wilt the spinach (if using fresh). In a skillet over medium heat, sauté the spinach with a splash of olive oil and a pinch of salt for 1–2 minutes until just wilted. Transfer to a cutting board and roughly chop. If using frozen spinach, thaw and squeeze out as much water as possible.

Make the creamy topping. In a bowl, mix the softened cream cheese, yogurt (or sour cream), mayonnaise, minced garlic, lemon zest, lemon juice, remaining salt and pepper, and red pepper flakes. Stir until smooth.

Fold in veggies and cheese. Add the chopped artichokes, spinach, 1/2 cup mozzarella, and 1/4 cup Parmesan. Stir to combine. The mixture should be thick but spreadable.

Assemble. Spread the spinach artichoke mixture over the chicken in an even layer. Top with the remaining mozzarella and Parmesan.

Bake. Place in the oven and bake for 22–28 minutes, depending on thickness, until the chicken reaches an internal temperature of 165°F (74°C) and the top is bubbling.

Broil for color (optional). Set the oven to broil for 1–2 minutes to brown the top lightly. Watch closely to avoid burning.

Rest and serve. Let it rest for 5 minutes. Sprinkle with fresh parsley or basil. Serve with rice, buttered pasta, roasted potatoes, or a simple green salad.