If you love mushrooms, this sauce will hit the spot. You could use it as a topping for pastas, meats, and—my favorite—polenta. The secret to a rich, deeply flavorful sauce is to use a variety of mushrooms, preferably the wild varieties. I’m partial to cremini, oyster, and shiitake, but you could also add portobellos, hen-of-the-woods, chanterelles, or any other variety you find. The only ones I’d steer clear of are regular white button mushrooms. Their mild flavor will get lost amid the stronger tastes of the wild varieties, and their high water content will thin your sauce without providing much flavor.
In a Large Skillet, heat the oil over a medium flame. When almost smoking, add the onion and garlic and sauté until the onion is tender, about 8 minutes. Add the mushrooms, ½ teaspoon of salt, and ¼ teaspoon of pepper. Increase the heat to high and sauté until the mushrooms are tender and all the liquid has evaporated, about 8 minutes. Remove the pan from the heat and add the Marsala. Return the pan to the heat and simmer until the Marsala evaporates, about 5 minutes. Add the chicken broth and simmer until the sauce has reduced by half, about 30 minutes. Remove the pan from the heat and stir in the cheese, basil, and parsley. Season the ragù with more salt and pepper to taste. (The sauce can be made up to 2 days ahead. Cool, then cover and refrigerate. Rewarm before using.)