In a shallow bowl, combine all-purpose flour, garlic salt, kosher salt, black pepper and Italian seasoning and mix together.
Coat each chicken breast thoroughly in the flour mixture.
Heat a skillet over medium-high heat. Pour in olive oil and butter.
Fry the chicken for a couple of minutes, until browned and then flip. Add in mushrooms as the chicken browns on the other side.
Pour the marsala wine over the chicken. Cover skillet with lid and reduce heat to medium-low and cook for about 10 minutes, or until chicken is cooked through, mushrooms are tender and sauce is thickened some.
Serve with steamed veggies for a lower carb dinner but also delicious with pasta or mashed potatoes. Enjoy!