Wash the zucchinis thoroughly and cut off the ends. Chop the zucchinis into small chunks.

Peel and chop the onion and garlic cloves finely.

In a large pot, heat the olive oil over medium heat. Add the chopped onion and sauté for 5 minutes until softened.

Add the minced garlic and sauté for another minute until fragrant.

Add the zucchini chunks to the pot and stir for about 2-3 minutes.

Pour in the vegetable broth, and add salt and black pepper. Bring the mixture to a boil, then reduce the heat and let it simmer for 15 minutes, or until the zucchini is tender.

Using an immersion blender, carefully blend the soup until smooth. Alternatively, blend the soup in batches using a regular blender, being cautious with the hot liquid.

Once blended, stir in the heavy cream and heat for another 2 minutes on low heat, without boiling.

Taste and adjust seasoning if necessary before serving.

Ladle the soup into bowls and garnish with fresh basil if desired.

For a lighter version, you can replace heavy cream with Greek yogurt.

This soup can be made in advance and stored in the refrigerator for up to 3 days.

You can serve it hot or chilled, depending on your preference.