Fry two chopped shallots or a small chopped white onion with a crushed clove of garlic until soft. Add a good glassful of white wine (I like Chenin Blanc but I'd recommend anything unoaked), maybe two-pub-measures-worth and simmer til all the alcohol has evaporated. Then add a big pot of double cream and reduce until it reaches a satisfactory thickness. Just before serving stir in a knob of butter and a tablespoonful of chopped parsley and/or tarragon. This amount will serve four poured over roasted chicken supremes.
buy a can of campbells condensed mushroom soup, when you add water to thin it out add white wine instead, a friend of mine always does this and makes chicken and mushroom pies with white wine sauce