Dried Chilean wild mushrooms, sometimes known as Chilean porcini, are smokier than most other dried mushrooms. If you can't find them, dried Polish or European porcini, which are widely available, are also smoky and flavorful.
In a small bowl, cover the dried mushrooms with the boiling water and let stand until softened, about 20 minutes. Drain the mushrooms, reserving 2 tablespoons of the liquid; be sure it doesn't contain any grit. Press any excess liquid from the mushrooms, coarsely chop them and transfer to a plate.
In a large skillet, melt the butter in the olive oil. Add the shallots and cook over moderate heat, stirring occasionally, until wilted, about 2 minutes. Add the chopped mushrooms and garlic and 2 tablespoons of the Marsala and cook, stirring frequently, until the Marsala is slightly reduced, about 2 minutes. Add the bread crumbs and continue cooking, stirring frequently, until completely blended, about 3 minutes.
Scrape the crumb mixture into a large skillet and stir in the remaining 1/2 tablespoon of Marsala and the thyme. Season with salt and pepper and toast over moderately high heat, stirring, until the crumbs are lightly browned and crisp, about 5 minutes.
Make Ahead: The crumbs can be refrigerated for up to 3 days.
Serve With: Pan-roasted chicken breasts (stuff about 1/2 cup under the skin of each of 6 chicken breasts) or pork chops (press 1/2 cup of the crumbs onto each of 6 pork chops); pasta, such as spaghetti, rigatoni or fusilli (toss the crumbs with the cooked pasta, adding a little pasta cooking water, butter, Marsala and Parmesan cheese).
Notes: Chilean wild mushrooms, or porcini, are available at gourmet food stores or by mail order from Marché aux Delices (888-547-5471).