Warm 1 tablespoon of Wilson's Basil Flavoured Oil in a large pot over medium heat. Season the chicken pieces with salt and pepper, add to the pot, and brown for 4 to 5 minutes. Remove and set aside.
Add the remaining basil oil to the pot along with the onion, carrot, celery and leek. Cook for 8 minutes, stirring occasionally, until the vegetables begin to soften.
Stir in the garlic and cook for a further minute, until fragrant.
Return the browned chicken to the pot, add the potato, stock and bay leaf. Bring to a gentle boil, then reduce the heat and simmer for 20 minutes.
Add the courgette and cabbage or spinach, and continue to simmer for 10 more minutes, until the vegetables are tender and the chicken is cooked through.
Remove the bay leaf. Stir through the chopped parsley and check the seasoning, adding more salt and pepper as needed.
Ladle into bowls, finish each with a drizzle of Wilson's Basil Flavoured Oil, and scatter over a few fresh basil leaves before serving.