Shrimps a la Bordelaise

Place two tablespoonfuls of butter and one of flour in a saucepan
and brown over the fire. Stir into this one cup of stock, and add
two tablespoonfuls of finely chopped raw ham, a slice of onion, one
tablespoonful of chopped parsley. Simmer for ten or fifteen minutes.
Strain the same and add to it a cup of shrimps. Simmer again for a
few moments and add a teaspoonful of tomato or mushroom catsup. Season
with, salt and pepper, and serve in timbale cases.