Sauté Aromatics: In a large pot, heat the olive oil over medium heat. Add the diced onion and minced garlic, sautéing until translucent (about 3-5 minutes).

Cook the Zucchini: Add the chopped zucchini to the pot and pour in the vegetable broth. Bring to a boil, then reduce heat and simmer for about 15 minutes, or until the zucchini is tender.

Blend the Soup: Remove from heat and use an immersion blender to puree the soup until smooth. Alternatively, transfer to a blender in batches to achieve a creamy texture.

Add Creaminess: Stir in the heavy cream or coconut milk and chopped basil. Heat gently over low heat, seasoning with salt, pepper, and a splash of lemon juice if desired.

Serve: Ladle the soup into bowls, garnishing with croutons and additional basil for a beautiful presentation.