Preheat your oven to 350 degrees F. Drizzle olive oil on a rimmed baking sheet.
Remove stems from mushrooms, roughly chop and place in a small bowl. Remove gills from inside of mushroom caps and discard gills.
Melt butter over medium high heat in a saucepan. Add mushroom stems and onions. Cook, stirring frequently, for approximately 4 minutes or until tender. Add garlic and cook until fragrant (about 30 seconds).
Remove from heat. Add cream cheese, crab meat, bread crumbs, Italian seasoning, Old Bay Seasoning, salt and pepper. Stir well to combine.
Place mushroom caps onto baking sheet. Spoon crab mixture into caps. Sprinkle evenly with Parmesan cheese.
Bake for 20 minutes, or until heated thoroughly. Sprinkle with fresh chopped parsley.