Heat up olive oil in a pan on medium heat

Add chopped onions and garlic to pan and cook until soft

Add mushrooms and continue to cook for two minutes

Add the flour to the pan and stir until complelty blended in

Add the marsala wine to deglaze the pan

Add beef stock and place on medium low heat

Once the sauce warms up add the butter

Cook sauce until it has thickened

Salt and pepper to taste

Put sauce on top of either chicken or steak. Enjoy!