- Wipe mushrooms clean with a damp paper towel. Alternatively, under slowly running water, cup 2-3 mushrooms at a time in your hands. Quickly run them under the water, gently rubbing the mushrooms to remove any debris. Place on paper towels to dry. Pop out the stems by pushing them from side to side, leaving a hollow center. Roughly chop stems or briefly pulse in a food processor.
- Preheat broiler. Set rack one level down from the top.
- Place mushrooms hollow side up on a rimmed baking sheet or broiler-safe casserole in a single, flat layer.
- Drizzle with 1 1/2 tablespoons oil and sprinkle with salt and pepper.
- Broil mushrooms for about 7-10 minutes (depending on your broiler) until they are browned, and the mushrooms are tender.
- When done, roll mushrooms around in the liquid, drain, and place on a clean rimmed baking sheet or in a broiler-safe casserole dish. Discard the juices.
- In a medium sauté or fry pan, heat the remaining 1 tablespoon olive oil over medium heat. Add mushroom stems and cook until any moisture evaporates, and they are browned.
- Add shallot and cook until softened, stirring about 1-2 minutes.
- Add garlic and cook for 1 more minute.
- Add sun-dried tomatoes, spinach, and oregano. Cook until spinach is wilted and some of the moisture has cooked off.
- Pour filling into a bowl, stir in Parmesan.
- Taste filling and add a little salt and pepper.
- With a teaspoon fill the center of the mushrooms, mounding filling.
- Preheat broiler.
- Place filled mushrooms on a rimmed baking sheet or in a casserole, sprinkle with the last tablespoon of Parmesan.
- Broil until browned and heated through.
TIPS:
*This size mushroom might seem large, but mushrooms shrink a lot during baking.
Make-ahead Note: Mushrooms can be made a few hours ahead, covered, and refrigerated. Remove from the refrigerator about 30 minutes prior to broiling to get the chill off, then broil and serve hot.
