Wild watercress (Nasturtium officianale) is packed with nutrients but unlike shop-bought versions, must be cooked before eating. Try this sauce for a great and versatile way to make use of this foraged, water-loving plant — we've served it with a tantalising cheese soufflé to tempt your taste buds.
Watercress’s scientific name Nasturtium comes from the Latin words “nasus” and “tortus”, meaning to wrinkle the nose. This refers to the effect of the plant on the nasal passages, after its peppery hit. When blended with acids like white wine and vinegar, and mellowed out by smooth crème fraiche, that peppery poke of watercress becomes a fresh and lifting sauce that cuts through oily fish like salmon, or provides a brilliant contrast to this rich, cheese soufflé. Although soufflés have a reputation for requiring a bit of concentration in the kitchen, the finished dish is definitely worth it.
Although you may think of watercress predominantly as a salad leaf, the wild version should always be cooked before consuming, as plants foraged from water courses can harbour the parasite liver fluke. Watercress boasts an impressive nutritional profile and is famously rich in vitamins A and C, magnesium, iron, calcium and folic acid. It should only be cooked as much as is absolutely necessary therefore, to avoid destroying its nutrients.
To find wild watercress, look out for chalk streams, particularly in southern England where it thrives. It has a long season from April to October, though can sometimes suffer in the drier months. When foraging, be aware of two lookalikes: fool's watercress (Apium nodiflorum) and lesser water parsnip (Berula erecta). Both of these smell of carrot/parsnip when crushed, and while fool's watercress is edible, lesser water parsnip is poisonous. For more information, see our foraging guide.
For the soufflé (serves four): 40g butter
40g plain flour
300ml full fat milk
40g strong cheddar 30g strong blue cheese (eg Danish Blue) 20g freshly grated parmesan 3 tbsp freshly-grated parmesan
Butter for greasing the ramekins
For the watercress sauce:
1 tbs butter
2 small shallots
1 tsp English mustard
50ml white wine
150ml crème fraiche
Juice of half a lemon
- Start by preparing the watercress sauce, as you will need it ready-to-go when the soufflé comes out of the oven.
- Heat the butter in a frying pan and add in the shallots, cooking until translucent.
- Add in the wine and reduce for a couple of minutes.
- Stir in the watercress and cook through for 1min before removing the pan from the heat.
- Allow to slightly cool (in order to prevent any explosions from hot liquid under pressure) and transfer to a blender.
- Add the crème fraiche, mustard and lemon juice and then blitz to a sauce.
- Return to the pan and gently heat through before serving.
- Preheat the oven to 200C/180C fan.
- Use some softened butter to grease four ramekins.
- Sprinkle over the parmesan until the insides of the ramekins are coated and shake off any excess.
- Melt 40g of butter in a pan over a medium heat, then stir in the 40g plain flour and mix until smooth.
- Gradually add in the 300ml milk.
- Continue to heat, whisking continuously, for 5mins or until the mixture thickens.
- Remove the pan from the heat and add in the cheese, stirring until melted.
- Transfer the mixture to a large bowl and set aside to cool for 5mins.
- Separate 4 eggs, reserving the whites. Gradually stir the yolks into the cheese sauce until well mixed. Leave to cool to room temperature.
- Now for the tricky bit! Put the reserved egg whites in a clean bowl and whisk into stiff peaks.
- Stir one heaped tablespoonful of the whisked egg white into the cheese sauce, until well incorporated.
- Using a metal spoon, gently fold in the remainder of the egg white. Try to minimise stirring, to retain as much air in the mixture as possible.
- Place the ramekins on a baking tray and divide the mixture between them. Run your finger around the edge of each ramekin to create a ‘top hat’ effect, which will ensure the soufflés rise evenly. Sprinkle 1 tbsp finely grated Parmesan over the tops.
- Bake for 13-15 mins until springy, wobbly and well risen, making sure to not open the oven door while cooking.
Always stay safe when foraging. You need to be 100% sure of your identification, 100% sure that your foraged item is edible, and 100% sure that you are not allergic to it (it is good practice to always try a small amount of any new food you are consuming). If in doubt, leave it out!