Preheat oven to 350F. Thinly slice mushrooms and potatoes.
Generously oil a baking dish that will hold potatoes and mushrooms in a layer no more than 1-1/2 inches deep. In a large bowl, toss together mushrooms, potatoes, parsley or basil, garlic, salt and pepper.
Spread potato mixture in dish and bake about 45 minutes or until potatoes are tender, turning mixture halfway through. Let stand a few minutes before serving. Garnish with flat-leaf parsley and basil and serve.