In a large pot that is deep and wide add the olive oil and warm it up on medium heat; once warm, add the thinly sliced shallots and cloves of garlic, together with a pinch of salt, then mix well and cook until golden and soft on low heat.
Allow the onions to soften and turn a light golden-brown color.
Once the onions are soft, add the chopped zucchini and sauté for a few minutes.
Next, add the vegetable stock cube, the cashew nuts, salt, and black pepper to taste and mix well.
Add enough cups of water to just cover the vegetables in the large pot, then bring to a light simmer and allow the zucchini soup to cook for 15-20 minutes, or until the zucchini are soft.
Once the vegetables are soft, add the tarragon, parsley and the lemon juice; mix well and simmer for a further couple of minutes on medium heat.
Before blending, allow the soup to lightly cool down; you can blend the soup with an immersion blender or in a food processor to the consistency preferred.
Once blended, adjust the consistency of the soup by adding water - if desired, then bring back to a light boil for a couple of minutes.
Serve with crusty bread, rice, some grated cheese, or garlic croutons and enjoy!