Sweet potatoes like many other root vegetables lend themselves to many heart warming dishes during the winter months. The pepperiness of the watercress oil and the umami flavour of feta just elevate a simple but nutritional vegetable to a fine dining dish.
I am using dried rosemary to flavour the soup but if you have fresh, just put a sprig into the soup and remove before blitzing.
Ingredients (serves 4-6)
- 2 sweet potatoes, approx. 450g peeled and thinly sliced on a mandolin or with a sharp knife
- 2 large leeks, cut in two lengthwise and then sliced finely
- 1 medium sized onion, finely chopped
- 4 tbsp extra virgin olive oil
- ½ tsp dried rosemary
- ½ tsp ground coriander
- 1 chicken stock
- A small bunch of fresh coriander, chopped
For the watercress oil
- 75g water cress
- 200ml sunflower or rapeseed oil
- A squeeze of lemon
For the feta topped baguette slice
- 4 slices of French baguette
- 100g feta cheese
- 1 clove of garlic
- 2 tbsp extra virgin olive oil
- 1 tsp mustard seeds
To serve
- 2 tbsp of mixed sunflower and pumpkin seeds
Method
Preheat the oven to 200 0 C.
Put the seeds on a baking tray and roast for a fee minutes till you can smell the oils released from them. Remove and leave to go cool.
To make the soup, bring a large pan to a medium heat. Add the olive oil and chopped onion and leek and sweat for 6-7 minutes till transparent and soft. Add the sweet potato slices and stir to coat with the oil. Add the ground coriander and cook for 2-3 minutes longer before adding the stock. Bring the pot to the boil, reduce the heat, add the rosemary, season with some freshly ground pepper and sea salt, cover the pan and cook on a low simmer for 30 minutes.
While the sweet potatoes and leeks are cooking, make the watercress oil. Bring small pan with plenty of water to the boil. Drop the watercress into the water and blanch for 30 seconds. Drain and drop into a bowl with icy cold water. When the watercress is cool, drain, pat dry in a clean towel and transfer to a powerful blender. Add the oil and blitz for a couple of minutes till the oil is a vivid green colour and you can’t see pieces of the water cress. Drain in a muslin cloth over a bowl, season with a tiny pinch of salt and a small squeeze of fresh lemon which helps punctuate the watercress flavour. Put in a squeezy bottle and keep in the fridge till needed.
When the sweet potatoes have cooked, turn the heat off and leave the soup to cool a little. Blitz in a blender and return to the pan, passing through a sieve if you think it is necessary to get rid of any little lumps. Adjust the seasoning and return to a clean pan to warm up at the point of serving.
For the feta topped baguette slices, put the baguette slices in the toaster for a couple of minutes. Rub with the garlic clove and brush with the olive oil, top with the feta and put under a hot grill for 2-3 minutes till bubbling. Take out of the oven and sprinkle with the mustard seeds.
To serve, heat the soup up, spoon into a soup bowl, drizzle with the watercress oil and sprinkle with the toasted seeds and serve with the feta topped baguette on the side.