1 Peel grapefruit with a knife and remove white inner skin.
2 Cut grapefruit segments between separating membranes and collect dripping juice in a bowl.
3 Cut avocados in half, remove pits, peel away skin and cut flesh into 1 cm (approximately 1/2-inch) wide strips.
4 Rinse scallions and cut diagonally into thin rings.
5 Grind whole cardamom pods or the seeds from split pods in a mortar. Squeeze half a lemon.
6 Mix grapefruit juice, 2 teaspoons lemon juice, cardamom, oil, honey and allspice together in a bowl and stir. Season with salt and pepper.
7 Cut off bottom thick stems of watercress. Rinse watercress, spin dry and chop coarsely.
8 Mix watercress salad with about 1/3 of the dressing. Arrange avocado slices, scallions, grapefruit segments and marinated watercress on plates. Drizzle with remaining dressing and serve.