Horse-radish Sauce for Salmon. No. 1. (Mrs. Thomas.)
This sauce does also for fish rissoles or fish fritters.
Boil a slice of horse-radish 10 minutes in a teacupful of stock. In another stewpan have ready a good white roux made of 1 oz. of butter to 1 teaspoonful of flour. To this roux add the flavoured stock strained from the horse-radish; cook 5 minutes; stir in 2 raw yolks of egg, then mix all thoroughly.
Heat gradually to all but boiling point; then add 1 table-spoonful of good English vinegar before serving in a sauce-boat.
This sauce should look creamy.