Jerusalem Artichoke Soup with Hazelnut and Spinach Pesto
This soup was first served in NOPI topped with quickly pickled shimeji mushrooms. We’ve gone for a different garnish here but, if you want to reinstate the mushrooms, place 150ml rice vinegar in a small saucepan with 2 whole star anise, 1 small cinnamon stick, 1 tsp pink peppercorns, 1/2 tsp whole cloves, 2 tbsp sugar, 100ml water and 1 tsp salt. Bring to the boil, then reduce the heat to low and simmer gently for 5 minutes. Remove from the heat and set aside to cool, then add 200g mushrooms and spoon on top of the soup just before serving. Any leftover mushrooms are also delicious as part of a mezze spread.
- 1 tbsp olive oil
- 30g unsalted butter
- 2 banana shallots, thinly sliced (100g)
- 1 medium leek, trimmed, washed, halved lengthways and then thinly sliced, white part only (120g)
- 2 garlic cloves, crushed
- 1.2kg Jerusalem artichokes, peeled and thinly sliced 1–2mm thick
- 250ml dry white wine
- 500ml full-fat milk
- 700ml vegetable stock
- 10g chives, finely chopped, to serve
- coarse sea salt and black pepper
- For the hazelnut and spinach pesto:
- 50g blanched hazelnuts
- 1 tbsp hazelnut oil
- 2 tbsp olive oil, plus extra to serve
- 30g baby spinach
- 10g tarragon
- finely grated zest of 1 lemon
- 1 tsp white wine vinegar
- 1 small garlic clove, crushed
- 1-2 green bird's-eye chillies, de-seeded
Preheat the oven to 160°C/140°C fan/gas mark 3.
First make the pesto. Spread the hazelnuts on a baking tray and roast for 15 minutes. Remove from the oven and, once cool, roughly chop. Set aside 30g to serve and place the remaining 20g in the small bowl of a food processor with all the remaining pesto ingredients and 1/4 teaspoon of salt. Add 21/2 tablespoons of water and blitz to form a smooth and runny paste. Set aside until required.
Place the olive oil and butter in a large saucepan on a medium-high heat. Add the shallots and sauté for 3 minutes, stirring once or twice. Add the leeks and garlic, along with 11/2 teaspoons of salt and a good grind of black pepper, and cook for another 3–4 minutes, until soft but gaining no colour. Add the artichokes and cook for 12 minutes, stirring from time to time, until beginning to soften and caramelize. Pour over the wine, bring to a simmer and cook on a medium heat for 3–4 minutes, to reduce by a quarter. Add the milk and stock and bring to the boil. Skim the surface of any impurities, then reduce the heat to medium. Simmer for 50 minutes, stirring every few minutes until the artichokes are cooked through and completely soft. Remove from the heat and blitz well in a blender, until completely smooth, adding a bit more stock if you need to thin it down.
To serve, spoon the soup into bowls and drizzle with the hazelnut and spinach pesto. Sprinkle with the chives and remaining hazelnuts and serve at once, with a final drizzle of oil.