Ingredients

For the soup:

• 2 tbsp olive oil
• 1 large onion, chopped
• 1 celeriac (~600g), cut into chunks
• 600g potatoes, cut into chunks
• 1.5 litres vegetable stock
• 1 tsp saffron strands, lightly ground in a mortar
• finely grated rind and juice of 2 oranges

For the gremolata:

• 1 garlic clove
• 1 tsp coarse sea salt
• handful of flatleaf parsley, leaves only
• 2 tbsp olive oil, plus extra to serve

Method

1. To make the soup, heat the olive oil in a large pan and fry the onion for 3-4 minutes until softened, but not coloured. Add the celeriac and potato. Cover and cook, stirring occasionally, for 10 minutes. Stir in the vegetable stock, ground saffron, orange juice and half the orange rind. Bring to the boil, then simmer for 20 minutes until the vegetables are tender.
2.  Transfer to a food processor and process until smooth (you may need to do this in batches). Return to the pan and season to taste.
3. To make the gremolata, pound the garlic and sea salt to a paste with a pestle and mortar. Add the parsley leaves and olive oil and pound until a fairly smooth paste is achieved. (Alternatively, puree all the ingredients in a food processor.)
4. Reheat the soup and ladle into individual bowls. Spoon the gremolata onto the soup and scatter over the reserved orange rind. Serve with an extra drizzle of olive oil, if desired.

By Elizabeth, originally by Burza via Epicuria