Mix the flour, salt, garlic powder and pepper in a shallow bowl. Coat chicken in the flour mixture.
Heat 1 tbsp oil and 2 tbsp butter in a 12-inch pan or skillet over medium-high heat until shimmering.
Fry 2 of the chicken breasts 2 at a time until golden-brown (about 3 to 4 minutes per side). Transfer to warm plate, tent with foil and keep warm.
In the same pan with remaining pan grease leftover from the chicken, melt 1 tablespoon of butter.
Add the mushrooms and fry for 2-3 minutes until browned, scraping away at any of the leftover chicken bits off the bottom of the pan.
Add the garlic and cook until fragrant, about 1 minute.
Pour in the Marsala and broth & simmer until reduced by half and starting to thicken, (about 10-15 minutes).
Pour in cream and return the chicken to sauce. Cook until the sauce thickens (about 3 mins).
Garnish with chopped parsley and serve immediately.