Boiled beef with green sauce

1. Put the beef shank in enough cold water to cover it, bring to the boil and skim off the foam.

2. Add the cleaned vegetables and the bay leaf, season with salt and simmer over low heat for about 2 hours until tender.

3. For the green sauce, chop the seven herbs (parsley, chives, sorrel, watercress, chervil, borage, salad burnet) very finely or blend them.

4. Stir the sour cream smooth with the yoghurt and the mustard, then mix in the herbs.

5. Mash the yolk of the hard-boiled eggs into the sauce, add the finely chopped whites and finally season with salt and pepper.

6. Slice the cooked meat and serve it with the cold or lukewarm green sauce and boiled potatoes.

Tip: The classic Frankfurt green sauce is made from exactly these seven herbs - if one is unavailable, use a little more of the others and it still tastes fresh and lively.