Cook for 2 mins and then add the Marsala and reduce by half, then add the beef stock and leave to reduce by half again and then add the cream.
Season the sauce and add back in the escalopes and half of your parsley and leave on a low heat to stay warm.
Meanwhile, in another pan, add a small amount of oil and add your diced potatoes, cook on a medium high heat for a minute, then add a good amount of butter and cook on a high heat, stirring often, until golden brown.
Season well with salt & pepper and then take off the heat and add the rest of your garlic and parsley and mix well.