This is from "The Best International Recipe", from the Cooks Illustrated folks. You want mushrooms with caps about 1.5 - 2 inches in diameters.
- Wipe the mushroom caps clean. Remove stems completely.
- Rinse the roasted red pepper. Pat dry. Slice into thin strips.
- Put oven rack in lower one-third of oven and preheat to 450. Line a baking sheet with foil. Toss mushroom caps with oil, salt and pepper. Lay gill side down on sheet. Roast until they release juices and shrink, about 25 minutes.
- Remove them from oven. Let cool slightly. When cool enough to handle, flip, fill with cheese and place a few strips of red pepper on top. (At this point, they can be covered and chilled for up to 2 days. You may need to cook them a couple extra minutes tho.).
- Bake until mushrooms are hot and cheese is melted and bubbling, about 20 minutes. Remove to serving platter. Sprinkle with parsley and let sit for 5 minutes before serving.