Remove the stalks from the beetroot and cut into 1cm chunks, no need to peel.

Peel the onion and chop into segments - like an orange. Put into a large roasting tray with the beetroot and drizzle with the olive oil. Sprinkle over most of the thyme and put in the oven at 170 degrees for 30-40 minutes, until the veg is softened.

When the veg is cooked, tip it into a large saucepan (take out any tough sprigs of thyme) and cover with the stock. Bring to the boil, taste and season with salt and pepper.

Blitz the soup in a food processor until smooth.

To serve, top eash bowl of soup with a dollop of soured cream.