Preheat your oven to 400°F. Place the mushrooms on the baking sheet and drizzle with oil, toss to coat. Roast the mushrooms for 10 minutes. Carefully drain any liquid that has accumulated. (If there isn't too much liquid, paper towels work nicely for removing any excess liquid.)
Season with salt and pepper. Continue roasting for an additional 10-15 minutes until browned with slightly crispy edges.