Preheat an oven to 350 degrees F. Toast the hazelnuts until the skins have begun to separate from the nuts, about 12 minutes. Remove from the oven and let cool briefly, then rub them in a towel to loosen the skins. Chop finely.

Trim the base of each artichoke so that it will stand uptight. Slice 2 inches off the top. Soak the artichokes in salted water for 20 minutes, then flush with running water. Steam, covered, over boiling water, until a leaf comes out fairly easily when tugged, about 3 minutes. Turn them upside down on a tack to drain.

Meanwhile, to make the filling: Warm the oil in a skillet over medium heat. Add the onion and garlic and cook, stirring occasionally, until limp, about minutes. While the onion is cooking, drain the porcini, reserving the liquid, and chop finely. Add the porcini and the fresh mushrooms to the onion, raise the heat to high, and cook, stirring frequently, until the mushrooms have released their liquid and begun to color, about 7 minutes. Season with the salt, pepper, parsley, and marjoram and stir in the bread crumbs, nuts, and half of the cheese. The mixture should be moist and fluffy. If it seems dry, add some of the reserved mushroom soaking liquid and fluff it up with a fork.

Scoop out the chokes from the center of each artichoke and discard. Fill the cavities with the filling and then stuff the remainder into the base of the leaves.

Preheat an oven to 375 degrees F. Set the artichokes in a baking dish. Add water or water mixed with white wine to reach 1/2 inch up the sides of the dish. Drizzle olive oil over the top, cover with foil, and bake for 20 minutes, Remove the foil, sprinkle the remaining cheese over the tops and down into the leaves, and continue to bake, uncovered, until the cheese and filling begin to brown, about 5 minutes longer. Serve hot.