I am Italian and therefore I love pasta. Some days I want anyway to have a light lunch,with pasta OBVIOUSLY but I do not want to use any heavy sauce on top. That's when I use veg for my recipes! In this case I used frozen mushrooms (that I really like). I buy them in Iceland , here the link, I think they are really tasty as they have also porcini mushrooms in it.
I often buy frozen food as I can keep it in my freezer and use it whenever I need. I think it is really useful as I can buy meat and vegetables for the whole week without going to the supermarket every few days.
About the mushrooms stock cube, you can import it from Italy, or buy the one I have used in here.
I have also seen that Kallo, the organic brand for stock cubes sell it, have a look here.