Mix together the Worstershire sauce
, mushroom ketchup, mustard, 2 tablespoons butter, cayenne pepper and salt and pepper.
Clean the kidneys by removing the outer skin and cutting away the core
. Cut each kidney into three or four pieces. Heat the remaining 2 tablespoons butter
with the oil in a frying pan
and cook kidneys for 4 to 5 minutes, turning occasionally. Pour the sauce mixture over the kidneys and stir for 1 to 2 minutes to coat the kidneys
Serve on warmed plates, sprinkled with parsley and accompanied by lemon wedges and hot buttered toast.