Add the white wine, 400ml water, Simon Gault Home Cuisine vegetable stock concentrate and my chicken stock concentrate to a pan. Bring to the boil and simmer gently for 5 minutes. Add cornflour to quarter of a cup of water and whisk out any lumps. Slowly pour the cornflour water mixture to the pan. Bring to the boil whilst stirring continuously and simmer for 5 minutes. Then serve.