Heat olive oil in a heavy-bottomed soup pot over medium heat.
Add the onion, celery, and two cloves of the chopped garlic.
Sauté for about 3 minutes, until the onion is soft and translucent.
Pour in 3 cups / 710 ml of water and add the zucchini, chickpeas, cumin, cayenne, salt, and pepper.
Bring the mixture to a simmer.
Cover the pot, reduce the heat to low, and cook for 10 to 15 minutes, or until the vegetables are tender.
Carefully transfer the soup to a blender.
Add the remaining clove of chopped garlic, walnuts, parsley, and lemon juice.
Blend until completely smooth, working in batches if necessary to avoid overfilling.
Serve immediately while hot, or chill to enjoy cold.
Garnish with a drizzle of olive oil, a sprinkle of smoked paprika, or some toasted pumpkin seeds for added flavor and crunch.
