Peel and slice the onion, garlic, and zucchini.
Heat up the oil in a large pot, and once warm, add the onion, garlic, and a little salt. Mix and allow to cook on low-medium heat until the onions turn transparent and the garlic loses its rawness.
Next, add zucchini, cashews, and the stock cube. Cover the vegetables with just enough water and bring to a boil on medium-high heat.
When the zucchini soup is boiling, reduce the low-medium heat and allow it to simmer lightly for 20 minutes or until the zucchini are thoroughly cooked and soft.
A couple of minutes before removing from the heat, add the fresh or dry herbs of choice.
Once ready, remove from the heat and allow the soup to cool down a little before blending.
Add the soup to a blender to blitz, and allow it to become completely smooth. This method allows the zucchini soup to become very creamy while not leaving any piece of vegetable. Should you not have it, an immersion blender is a good alternative to use.
Add salt and pepper to taste before serving.
You can enjoy this soup cool or warm, and it is perfect served with a nice slice of crusty bread, a sprinkle of Parmesan cheese, and a little drizzle of fresh olive oil.