I bought some oyster mushrooms at the store last week.
I decided to roast them with some onion. I set the oven for 375, then prepared the mushrooms. I washed them, then cut them into their individual mushroom pieces. (I saved the thick core in a container in the freezer for later use as veggie stock.) I added sliced onions, salt, pepper, thyme, and olive oil, then stirred.
I roasted them for about 30 minutes, stirring every 10 minutes for the first two times, then every 5 after the first 20 minutes. They probably were fine to eat after 20 minutes, but I wanted the onions to cook more.
These roasted mushrooms make an easy side dish. Any type of fresh mushroom should be good roasted, although cooking times are likely to vary.