Preheat the oven to 400°F (200°C) and grease a 9x13-inch baking dish.

Slice each chicken breast in half horizontally to create thin cutlets and pound the thicker ends for even cooking.

In a bowl, mix 1 tablespoon of olive oil, minced garlic, Italian seasoning, salt, and pepper. Coat chicken cutlets in the marinade and refrigerate for 15–30 minutes.

Heat remaining olive oil in a skillet over medium heat and sauté spinach for 2–3 minutes until wilted. Remove from heat.

Beat softened cream cheese until smooth, then stir in sautéed spinach and ½ cup of mozzarella cheese.

Optionally sear marinated chicken in a hot skillet for 1–2 minutes on each side until lightly browned.

In the baking dish, layer the seared chicken cutlets, spread the spinach and cream cheese mixture over them, then top with remaining mozzarella cheese.

Bake in the oven for 20–30 minutes or until chicken reaches 165°F (75°C) and cheese is bubbly and golden.

Let the casserole rest for 5 minutes before slicing and serving.