Preheat the oven at 375 ° F (190 ° C). Lightly lubricate a baking dish or line with parchment paper.
Clean the mushrooms and remove the stems. Finely chop the stems and set it aside.
Sauté vegetables: In a pan, melt butter on medium heat. Add celery, onion, green bell chili, and chopped mushroom stem. Until soft (about 5 minutes).
Mix stuffing: In a large bowl, mix sautéed vegetables, crabs, breadcrumbs, garlic powder, black pepper, paprika, mozerela, parameson cheese and mayonnaise. Stir until well mixed.
Fill the mushrooms: Use a spoon to make each mushroom cap with the mixture generously.
Bake: Arrange stuffed mushrooms in the prepared baking dish. Bake for 18-20 minutes or until the top turns golden and mushrooms are tender.
Garnish and service: Let it cool for 5 minutes. If desired, sprinkle with fresh parsley before serving.