Lobster salad with watercress

INGREDIENTS
1⁄2 red onion, finely sliced
1 tsp red wine vinegar
4 cooked lobster tails, halved
1 large bunch of watercress, tough stalks removed
1⁄2 fennel bulb, very finely sliced
8 sun-dried tomatoes, chopped
fresh herbs, such as chervil, dill,
or chives, to garnish
For the dressing
1 egg
1 egg yolk
2 tsp Dijon mustard
zest and juice of 1 lemon
400ml (14fl oz) sunflower oil
10g (1⁄4oz) chervil or chives
salt and freshly ground black pepper

METHOD
To make the dressing, place the egg, egg yolk, mustard, and lemon zest and juice into a blender. Blend on a low speed and slowly add the oil. Add the chervil. Season to taste with salt and pepper. Set aside.
Place the red onion in a bowl with the vinegar, and leave to stand for 10 minutes.
Remove all the meat from the lobster tails, keeping the pieces of meat as whole as possible, then slice them thickly.
Arrange the watercress on plates, scatter over the fennel, the drained onion slices, and the tomatoes. Place the lobster meat on top, drizzle over the dressing, and garnish with fresh herbs.