Liquidise if you like smoother soup.
NB. I just made some yesterday and as I hadn't got any fresh herbs in stock I just sprinkled in some spices from my spice rack and it was still lovely.
I always tend to add Mixed Herbs and some Black & Red Pepper from my spice rack to most soups.
The main ingredients (mushrooms in this case) and the Stock Cubes are the only important ingredients really.