Thinly slice the celery; finely chop the fennel & garlic; slice the leek; peel & chop the celeriac.
Heat the oil in a large saucepan, then gently cook the chopped vegetables for about 10 minutes. Add the rosemary, stir for a couple of minutes.
Pour in the vegetable stock, bring to the boil.
Cut the green beans into 1 cm pieces.
Add the beans and the green beans to the pan and cook for 5 minutes.
Add the spinach and cook for 2 minutes.
Remove & discard the rosemary sprigs.
Serve the soup warm, sprinkled with grated cheese and a dollop of green pesto, if liked.