Clean the mushrooms by rinsing with a forceful spray of cold water to remove any dirt. Pat the mushrooms dry with a paper towel, then remove the stems from the mushrooms. Take the head of the mushroom into your palm, stem up, and press the stem sideways. It should pop off/out easily. (Save the stems for a different recipe or compost.)
Next, use a melon baller or a small spoon to further hollow out the mushrooms. Be gentle with this process, as raw mushrooms are tender and breakable, and we need them whole so they can hold all of that cheesy crabby goodness inside. Scoop out the gills and some of the “roof” of the mushroom to create that extra space. Set the hollowed-out mushrooms aside and start preparing the filling.
Mix the cream cheese, goat cheese, onion, lemon juice, Worcestershire sauce, granulated garlic, and lemon pepper in a mixing bowl until combined. Fold in the crab meat. Taste and season with salt, as needed.
Fill the mushroom caps with the crab mixture, place in a lightly greased baking dish, and top with the Parmesan cheese and parsley. (Recipe may be prepared to this point and refrigerated, covered, overnight.)
Bake at 425ºF for 20 minutes until mushrooms are soft and the filling is browned in spots. Serve warm.