Trim the leaves from the beetroots, taking care not to cut the skin. Rinse under running water and place in a large pan of water. Bring to the boil then simmer for 30 minutes or until the beets can be easily pierced with a fork.
Lift the beets out of the water and leave to cool for a few minutes. When they are cool enough to handle, peel off the skin and cut into thick slices.
Toast the caraway seeds in a small frying pan for a couple of minutes.
Make the dressing by mixing together the oil and vinegar, a little salt and the toasted caraway seeds.
Wash the watercress and remove the hard stalks. Wash the spinach and rocket leaves, mix with the watercress and divide between two plates.
Dice the feta. Top the leaves with the cheese and the beetroot. Drizzle with the dressing and serve.