When does a weed become a herb? Or rather, how does a herb become a weed? Watercress is one of the oldest known leaf herbs consumed by humans. It is an aquatic flowering plant and even though most of the watercress we now use is farmed, plenty can still be found in many rivers around Ireland. Of course, you need to know that the river is clean and that the watercress is always cut above the water line.
Watercress is a truly ancient Irish herb and would have been paired with salmon, trout and pollan. While we may all be familiar with the first two fish, the latter is a fish unique to Ireland and can only be found in five Irish lakes, namely, Lough Neagh, Lower Lough Erne, Lough Ree, Lough Derg and Lough Allen.
Younger watercress is good in a salad or as a garnish, whereas the older leaves are better for soups and purée. I prefer to make a purée and then turn it into a soup if needed, as opposed to the other way around. The purée can be frozen for up to six months and can be combined with nettles, spinach, ground elder or nasturtium.
How to make watercress purée for fish
Take 200g of watercress and 200g of spinach and blanch in boiling water for one minute. Refresh in ice water and then strain. Fry one sliced onion in 50g of butter with two minced garlic cloves. When the onions are soft, add 300ml of cream. Reduce the cream by half and then add the spinach and watercress into the sauce. Place in a food processor with another 50g of butter and a judicious amount of sea salt.
Blend until smooth and then pass through a fine strainer if desired. At this stage you can freeze the purée or place in fridge until needed. Heat the purée by gently warming it in a pan, or one minute in a microwave. Serve with poached salmon or fried pollan. The purée also works well with chicken or beef.
