Preheat oven to 325 degrees. Spray a rack with nonstick spray and place in a roasting pan. Season the beef with the salt and pepper. Roast beef for 1 hour, or until it reaches your desired doneness. Transfer roast to a cutting board and let stand for 10 minutes.
When roast is resting, prepare mushrooms. Heat the olive oil in a skillet. Saute the onion until softened. Add the garlic and frozen bag of mushrooms. Saute, stirring constantly, for another 5 minutes. Stir in the wine and thyme and cook, stirring constantly, until the mushrooms are softened, about 5-6 minutes. Slice the beef and serve with some mushrooms spooned over the top. Serve immediately. Serves 6-8.
*If you can't find the bag of mushroom medley at your Trader Joe's, or you don't have a Trader Joe's nearby, you can substitute about 3 cups of fresh mushrooms, preferably a mix of shiitake, cremini, and porcini, or your favorites.
Recipe by The Culinary Cellar at https://theculinarycellar.com/roast-beef-with-a-mushroom-medley/