Place a large saucepan over a medium low heat. Add the onions and cook until softened and slightly golden on the edges. Add the celery, carrot and zucchini and cook until lightly caramelised. Add the garlic and cook until fragrant.
Add the spices and harissa and cook for a couple of minutes, until fragrant and aromatic. Stir well making sure the spices don't catch and burn as this will make them bitter.
Add the tomatoes and vegetable stock and season with salt and pepper and simmer for 20 minutes.
Add the cannellini beans and capsicum (bell peppers) and simmer for 10 to 15 minutes. Just before serving add the parsley and stir through before ladling into bowls.