Prepare the Mushrooms

1. Preheat the Oven: Preheat your oven to 375°F (190°C).
2. Clean the Mushrooms: Gently wipe the mushrooms with a damp cloth to remove any dirt. Remove the stems and set the caps aside.

Make the Filling

1. Mix the Filling: In a medium bowl, combine the crab meat, cream cheese, Parmesan cheese, breadcrumbs, mayonnaise, Dijon mustard, garlic powder, Old Bay seasoning (if using), green onions, parsley, salt, and pepper. Mix well until everything is fully incorporated.
2. Taste and Adjust: Taste the filling and adjust the seasoning as needed.

Stuff the Mushrooms

1. Fill the Caps: Using a spoon or your hands, generously fill each mushroom cap with the crab filling, pressing it down gently to pack it in.
2. Drizzle with Olive Oil: Place the stuffed mushrooms on a baking sheet lined with parchment paper. Drizzle a little olive oil over the tops of the stuffed mushrooms for added flavor and moisture.

Bake the Mushrooms

1. Bake: Place the baking sheet in the preheated oven and bake for 15-20 minutes or until the mushrooms are tender and the tops are golden brown.
2. Cool Slightly: Remove the stuffed mushrooms from the oven and let them cool for a few minutes before serving.