Preheat your oven to 400°F (200°C).
This ensures even cooking for your stuffed mushrooms.
Remove the stems from the mushrooms and set them aside.
Clean the caps thoroughly to remove any dirt.
In a skillet over medium-high heat, add olive oil.
Cook the onion and red bell pepper for 2-3 minutes until they soften.
Add the chopped mushroom stems and cook for another 2 minutes.
Combine the cooked vegetables, crabmeat, panko, cheddar, cream cheese, parmesan, Old Bay, salt, and pepper in a bowl.
Mix well to create a smooth stuffing mixture.
Fill each mushroom cap generously with the stuffing mixture.
Place on a baking sheet and bake for 15-20 minutes until golden brown