Halve the zucchini and cut into pieces. Pluck the thyme leaves from the stems. Peel the onion and garlic, chop them roughly and fry them with the zucchini pieces in hot oil until light brown.
Add thyme and fry briefly. Pour in the vegetable stock and let everything simmer gently for about 15 minutes.
Finely puree the soup with a hand blender or press it through a sieve and season with salt and pepper.