How to Make It
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.