Preheat oven to 450°F. Line a baking sheet with parchment paper, or brush a pan lightly with olive oil.
Remove stems and gills from mushrooms. Chop stems for filling and set aside. Place prepared caps on the baking sheet.
Check crab mixture for any pieces of shell. Set aside.
Shred mozzarella cheese.
In medium skillet, over medium heat, heat olive oil and cook chopped stems until tender, about 10 minutes.
Stir in crab meat, garlic salt, cayenne pepper, blend together.
Add in shredded cheese and bread crumbs. Folding into crab filling. Blend together well. Remove from heat.
With a spoon scoop crab mixture and place in mushroom cap. Make sure the cap is heaping full with the crab mixture
Place on prepared baking sheet. Bake for 15 minutes
Remove from oven, garnish with chopped parsley or chives, and serve warm