Put the chicken in a saucepan and cover with the stock. Bring to a boil, then reduce the heat and simmer for 10 minutes. Turn off heat, cover the pan and leave for 15 minutes more, or until cooked through. Remove the chicken, cool for a few minutes, then tear into shreds.

Put the dressing ingredients in a large bowl and mix. Add the shallots and soak for 10 minutes.

Cut the top and bottom from the grapefruit. Place on one end on a chopping board, then, using a sharp knife, slice off the peel and pith in downward strips, following the line of the fruit. Holding the grapefruit in one hand, carefully slice down on either side of the papery membranes to release the segments and add to the dressing. Squeeze the juice from the membranes of one of the grapefruit over the top.

Add all the remaining salad ingredients to the dressing, but keeping back a handful or two of peanuts. Toss lightly together, leave to stand for a couple of minutes, then divide between bowls, pouring over any leftover dressing and sprinkling with the remaining peanuts.