Every cook in our part of Istria had her own version of wild mushroom soup. This one was devised by my Great Aunt Santola, a widow, who cooked the soup for the whole courtyard at Busoler. She would come home and pick over the mushrooms she had gathered, separating those to be sauteed from those earmarked for other uses. Mostly trimmings and stems were reserved for her soup. When I was old enough to begin gathering my own mushrooms, I was allowed to pick only the unmistakably safe varieties, like champignons and porcini, and forbidden to eat any before my aunt approved them. The traditional belief was that the poisonous mushrooms could be detected by cooking them in water with a piece of brass; if the brass turned green, the mushrooms were unsafe. As a further precaution, the oldest woman in a household had the dubious honor of tasting the mushrooms before they were served to other members of the family
In 1½ cups of warm water, presoak the dried porcini about 20 minutes, until softened. Drain, reserving all but the last 2 teaspoons of the steeping liquid (to avoid unwanted sediments), remove and rinse the softened porcini.
In a 5-quart pot, heat 5 tablespoons olive oil, add the bacon and onion, and sauté until translucent. Add the potatoes, carrots, and shallot, and cook 2 minutes over medium heat, stirring constantly. Add the stock, drained porcini, reserved soaking liquid, and salt, and bring to a boil. Reduce the heat and keep on low boil about 10 minutes, until the vegetables are tender.
To prepare the fresh wild mushrooms, heat the olive oil in the large skillet and sauté them in batches, over medium-high heat, until all water has evaporated, about 7 minutes per batch. Transfer the mushrooms to the soup pot and simmer 30 minutes, skimming occasionally. Add the pepper and parsley, and serve piping hot.
The soup is best when made with several varieties of fresh wild mushrooms (porcini, shiitake, chanterelle, hen-of-the-woods, etc.), but even a single variety will produce an excellent soup. Other types of dried mushrooms may be substituted for the dried porcini specified, but porcini are preferable.