The traditional recipe may use Frosts Bolete (Butyriboletus frostii) but you can substitute with most mushrooms from store brought to puffballs that I use here.
Heat the oil in the pan and sauté the green pepper, onion and parsley. Sauté until the onion is softens and turns translucent.
Add the sweetcorn, mushrooms and crumbled stock cube or stock concentrate. Stir, cover and cook over medium heat for 5 minutes.
Uncover and cook another five minutes or so, sprinkle with black pepper and serve.