In a large bowl combine chicken, oil, salt and pepper, garlic powder, and Italian seasoning and toss.
In a large skillet over medium heat, brown the chicken on both sides for 2-4 minutes. Transfer chicken to a plate and cover to keep warm.
Add butter to pan and stir until melted. Stir in garlic and mushrooms. Continue to cook 3-4 minutes over medium-high heat until butter begins to darken and mushrooms are tender.
Sprinkle flour into the pan and stir to combine. Whisk in chicken broth and milk or heavy cream. Stir in parmesan cheese and salt and pepper to taste.
Return chicken to pan and spoon a little of the sauce over the chicken. Cover and bake at 375 for 15-20 minutes until chicken is cooked through.
Spoon more sauce over the chicken and sprinkle with cracked black pepper, grated parmesan cheese, and fresh parsley or thyme and serve immediately.
