Begin by poaching the eggs:

fill a medium-sized frying pan with water to a depth of approximately 11/2 inches (4 cm), then heat it to a temperature just sufficient to keep the water at a bare simmer. Then break the eggs, 5 or 6 at a time, into the simmering water and let them cook, uncovered, for 2 minutes. If you find it hard to break the shells, carefully make a cut in the shell with a small serrated knife before you break them into the water. Then, use a draining spoon and a wad of kitchen paper underneath to lift them from the water and transfer them to a bowl of cold water. Then continue to cook the remaining eggs in the same way, and leave them in a bowl of cold water until you are ready to use them.

For the sauce, separate off the watercress leaves and discard the stalks. Now break the egg into a food processor or blender, add the salt, garlic, mustard powder and a few twists of freshly milled black pepper, then switch on to blend these together. Now mix the oils in a jug and pour in a thin trickle through the hole in the top with the machine still switched on. When all the oil is in, add the vinegar, lemon juice, watercress and tarragon leaves, then blend again until the leaves are quite finely chopped.

To serve, arrange salad leaves on each plate and arrange 3 poached quails eggs in the centre of each one. Drizzle some of the sauce over the top of each salad, followed by a sprinkle of a few snipped chives. Serve with crusty bread.