This sauce can be made in either of the following ways:
- Well blanch for 2–3 minutes, 100 g (3½ oz) sorrel, parsley, tarragon, chervil, chives and very fresh salad burnet in absolutely equal proportions, plus 60 g (2 oz) each of watercress leaves and spinach leaves. Drain well, refresh and squeeze out all the water. Place in a mortar and pound well adding and mixing in 6 freshly cooked hard-boiled egg yolks. Pass through a fine sieve and place the purée in a basin. Add a pinch of salt and pepper and 5 raw egg yolks; then proceed as for Mayonnaise by adding 8 dl (1⅖ pt or 3½ U.S. cups) oil and a little vinegar as necessary. Finish the sauce by adding 1 tbs Derby Sauce.
- Prepare the purée in the same way and in the same proportions as for Sauce Vincent 1) adding it to 9 dl (1⅗ pt or 4 U.S. cups) Mayonnaise; correct the seasoning and finish with the Derby Sauce.
This sauce is particularly suitable for serving with cold fish and shellfish.