How to Make It
In a very large skillet, melt 2 tablespoons of the butter in the olive oil. Add the shiitake and oyster mushrooms and cook over high heat, stirring occasionally, until lightly browned, about 6 minutes. Scrape the mushrooms to 1 side of the skillet.
Melt the remaining 1 tablespoon of butter on the other side of the skillet. Add the shallot and cook, stirring occasionally, just until softened, 1 to 2 minutes. Stir the shallot into the mushrooms and cook for 2 minutes longer.
In a medium bowl, whisk the Madeira with the miso. Add to the mushrooms and cook over moderately high heat for 1 minute, scraping up the browned bits from the bottom and sides of the skillet. Add the broth, parsley and thyme and simmer until the sauce is slightly reduced, about 2 minutes. Season the mushrooms lightly with salt and pepper. Transfer to a large bowl and serve.