Heat 1 tbsp of the oil in a large saucepan or casserole pot. Fry the onion and celery gently for 5 mins. Add the crushed garlic and cook for 1 min more. Tip in the carrots, stock and thyme, then season and bring to the boil. Lower to a simmer and cook, covered, for 25 mins until the carrots are softened.

Meanwhile, heat the oven to 220C/200C fan/gas 7. Rub the whole garlic clove over both sides of the sourdough. Tear it into rough chunks and toss with the remaining oil, a good pinch of salt and the seeds. Spread out on a baking sheet and bake for 8-10 mins until golden and crisp. Mix with the chopped parsley and set aside.

Remove the thyme from the pan and discard. Blitz the soup with a hand blender until smooth. Stir though the cream and season to taste. To serve, ladle the soup into four bowls, top with the croutons and drizzle over a little extra cream, if you like.