Preheat the oven to 200C/400F/Gas 6.

Place the cubes of swede in a roasting tray. Drizzle over two tablespoons of the olive oil and season.

Roast in oven for 25-30 minutes until golden brown and tender, stirring occasionally.

Meanwhile, heat the remaining tablespoon of oil in a large heavy-based saucepan, stir in the onion, carrots, celery, garlic and thyme leaves and fry for 4-5 minutes until softened but not browned.

Add the roasted swede to the pan and pour over the stock.

Bring gently to the boil, cover and simmer for 25-30 minutes, stirring occasionally.

Purée the soup in a food processor or liquidiser until completely smooth. Pass through a sieve for an extra fine texture if preferred.

Transfer the soup back to a clean saucepan. Stir in most of the cream, reserving some for garnishing. Gently heat through and adjust the seasoning if necessary.