Combine the 2 cups hot water and the porcini mushrooms, let stand until the mushrooms are soft. About 30 minutes. Drain, reserving soaking liquid. Squeeze porcini dry and chop coarsely.
Preheat oven to 325 degrees F (165 degrees C). Divide cubed bread between two baking sheets. Bake until beginning to brown. About 15 minutes. Cool then transfer to a very large bowl.
Melt the butter in a heavy Dutch oven over medium-high heat. Add the leeks, shallots, crimini or button and shiitake mushrooms. Saute until golden and tender, about 15 minutes. Mix in the celery and porcini mushrooms and saute for another 5 minutes. Transfer mixture to the bowl with the bread crumbs. Mix in the parsley, hazelnuts, thyme and sage. Season with salt and pepper and stir in the beaten eggs.
To Bake The Stuffing In A Turkey: Fill the main cavity with the stuffing. Combine the broth and 1/2 cup of the reserved porcini soaking liquid in a large glass measuring cup. Add enough broth mixture to the remaining stuffing to moisten. Spoon remaining stuffing into a buttered baking dish. Cover with buttered foil. Bake stuffing in dish alongside turkey until heated through, about 30 minutes. Uncover and bake until top is crisp, about 15 minutes.
To Bake All Stuffing in Pan: Preheat oven to 325 F. Butter 15x10x2-inch baking dish. Mix 3/4 cup reserved porcini soaking liquid and 3/4 cup broth into stuffing. Transfer stuffing to prepared dish. Cover with buttered foil and bake until heated through, about 1 hour. Uncover and bake until top is crisp, about 15 minutes.