Cook the Chicken: In a large skillet, heat 1 tablespoon of olive oil and 2 tablespoons of butter over medium heat. Season the chicken breasts with salt and pepper, then place them in the skillet. Cook for 4-5 minutes on each side, or until golden brown and cooked through. Once done, remove the chicken from the skillet and set it aside.

Sauté the Mushrooms : In the same skillet, add the remaining olive oil and butter. Add the sliced mushrooms and sauté until tender and lightly browned, about 5-7 minutes. Remove and set aside with the chicken.

Make the Creamy Parmesan Sauce: Add the minced garlic to the skillet and sauté for 30 seconds, until fragrant. Sprinkle in the flour and stir to form a roux. Cook for 1 minute. Slowly whisk in the chicken broth and heavy cream, stirring continuously to keep the mixture smooth. Add Add the Parmesan cheese, salt, garlic powder, and black pepper. Stir until the sauce thickens slightly, about 2-3 minutes.

Incorporate the Spinach: Add the fresh spinach and cook for 1-2 minutes, stirring, until it wilts down.

Combine and Serve: Return the chicken and mushrooms to the skillet, spooning the sauce over the chicken. Serve hot with your favorite side dishes like pasta, rice, or crusty bread.