Carefully remove mushroom stems an chop them finely.
Heat butter in a small skillet over medium heat. Sauté the stems with the garlic until mushroom stems begin to lightly brown. Let them cool slightly.
Mix the cream cheese, green onion, crab, soy sauce, Panko crumbs and pepper in a small bowl. Add the sautéed mushrooms and garlic. Mix well.
Fill the mushroom caps with cream cheese mixture. Sprinkle the mushrooms with the additional Panko crumbs. Place the stuffed mushrooms on a baking sheet lined with parchment.
Bake at 400F/200C for 15-20 minutes. Garnish with chopped parsley.