Heat 4 tablespoons of the olive oil in a large heavy-bottomed frying pan until smoking. Add the sliced fresh mushrooms and fry, stirring constantly, for 15-20 minutes or until the mushrooms have become very dark. Remove and keep warm.
Wipe clean the frying pan. Strain the porcini mushrooms, retaining their juices, rinse and squeeze dry. Heat another tablespoon of olive oil in the pan an