Original Receipt in 'The Cook and Housekeeper's Dictionary' by Mary Eaton (Eaton 1822);ROBERT SAUCE. Put an ounce of butter into a pint stewpan, and when melted, add to it half an ounce of onion minced very fine. Turn it with a wooden spoon till it takes a light brown colour, and then stir into it a table-spoonful of flour, a table-spoonful of mushroom ketchup, the like quantity of port wine, half a pint of weak broth, and half a tea-spoonful of pepper and salt mixed together. Give them a boil, then add a tea-spoonful of mustard, the juice of half a lemon, and one or two tea-spoonfuls of vinegar, basil, taragon, or burnet vinegar. This sauce is in high repute, and is adapted for roast pork or roast goose.