All equipment and ingredients should be warm, as in the previous mayonnaise sauce recipes.

1 egg
1 tbsp Dijon mustard
285ml (1/2 pint) groundnut or sunflower oil (Flora)
4 tbsp extra-virgin olive oil
3 tbsp hazelnut oil (optional)
3 tbsp tarragon or sherry vinegar
100-140ml (1/4 pint) warm water

For the green herby variation

1 bunch fresh herbs e.g. chervil, dill, chives, parsley
salt and freshly milled white pepper

Place the egg, in its shell in the blender jar, and fill with warm water, while you get the rest of the ingredients ready.

Stand the remaining ingredients in a warm place.

Empty and dry the blender jar, and whizz the shelled egg with the mustard for 20 seconds.

Add the oils in a slow steady stream through the hole in the lid, with the blender operatingon Speed 1.

Now add the water slowly and season.

Check the flavour - add morevinegar if required.

Store in the refrigerator in a bottle if not using immediately, for up to seven days.

For the green, herby variation

Chop the chives, if using; the other herbs may be added in a bunch.
Add the herbs after the water and blend until you have a beautiful pale green sauce.

Adjust the seasoning and blend again.