Watercress soup, or rather broth, goes back to ancient times in Ireland. As a native plant, it's probable that the first settlers, about 10,000 years ago, feasted on it in season, from spring to early summer. Its consumption as a broth would have to await pots and other cooking utensils which appear after the first farmers established themselves in Ireland. Indeed, hunter-gathers were not the best at making pots, hence that absence of soups in their diets.
For the smoother, more refined version of watercress we have to wait until the big houses of the 18th century, which often combined the best British and European sensibilities with local ingredients, such as watercress, nettles and sorrel.
Due to its peppery nature, watercress pairs well with fatty fish such as eel and salmon. The fact that both these fish were plentiful in Ireland and were often paired with watercress is no surprise. This soup can equally be prepared with spinach, sea beet, nettles or sorrel, or even a combination of all of them. You can also use it as a sauce and serve it with poached salmon or smoked eel.
Watercress soup
Roughly chop four onions and fry in 50g of butter in a large pot. Season with sea salt and add a few sprigs of fresh thyme, rosemary and sage. Cook the onions on a medium heat until blonde and translucent. Add 250g of peeled, chopped potatoes and cook for a few minutes. Warm 600ml of chicken or vegetable stock in a separate pot and then pour over the potatoes. Season again with a little sea salt. Bring to the boil and then simmer.
When the potatoes are cooked, add 300g of washed watercress and remove from the heat. Let the soup rest until the watercress goes bright green. Blend the soup until smooth. Add 300ml of cream and return the soup to the stove. Warm gently to avoid losing the soup’s fresh green colour. I like to blend again to ensure it is extra smooth. Finish with a little sea salt and a swirl of fresh cream or cold-pressed rapeseed oil.
