Preheat your oven to 375°F.
Clean the mushrooms using a damp paper towel to wipe away any dirt or debris. Remove the stems from the mushrooms and use a spoon to gently scoop out the inside of the mushroom cap, creating a hollow space for the filling.
In a mixing bowl, combine the crabmeat, cream cheese, Parmesan cheese, breadcrumbs, parsley, garlic powder, salt, and black pepper. Mix all the ingredients until well-combined.
Stuff each mushroom cap with the filling mixture, using a spoon to press it down and make sure the filling is tightly packed.
Spray a baking sheet with non-stick cooking spray, and arrange the stuffed mushrooms on it.
Bake the mushrooms in the preheated oven for 18-20 minutes, or until the mushrooms are tender and the filling is golden brown.