Prepare the Chicken : Preheat your oven to 375°F (190°C). Season the chicken breasts with salt and pepper, then lightly dredge them in the flour, shaking off any excess.

Sear the Chicken : Heat olive oil or butter in a large skillet over medium heat. Add the chicken and cook for 3–4 minutes on each side until golden brown (but not fully cooked). Remove the chicken and set aside.

Sauté the Vegetables : In the same skillet, add the mushrooms and onion. Sauté for 4–5 minutes until softened and slightly golden.

Make the Sauce : Stir in the cream of mushroom soup, milk, chicken broth, and garlic powder. Simmer for 2–3 minutes, stirring to combine.

Assemble the Dish : In a baking dish, spread a small amount of the sauce on the bottom. Arrange the chicken breasts in the dish and pour the remaining sauce over them.

Add the Cheese : Sprinkle the shredded mozzarella and Parmesan cheeses evenly over the top.

Bake : Bake in the preheated oven for 25–30 minutes, or until the chicken is fully cooked (internal temperature of 165°F/74°C) and the cheese is melted and bubbly.

Garnish and Serve : Sprinkle with fresh parsley for a pop of color and flavor. Serve hot with rice, pasta, or mashed potatoes.