Preheat the oven to 375°F (190°C).
Lightly grease a small baking dish or ovenproof skillet.
Soften the cream cheese so it mixes easily. Microwave it in short bursts if needed, just until spreadable.
Make the base: In a bowl, mix cream cheese, mayonnaise, shredded cheese, garlic, Old Bay, Worcestershire, hot sauce, lemon juice, and zest. Add a small pinch of salt and pepper.
Fold in the crab and green onion gently.
Don’t overmix—keep some bigger crab pieces for texture.
Taste and adjust seasoning. Add more Old Bay, lemon, or hot sauce as you like.
Transfer to the baking dish, smoothing the top. Sprinkle Parmesan over the surface for a golden crust.
Bake 18–22 minutes, until hot and bubbling around the edges and lightly browned on top.
Rest 5 minutes so it sets slightly.
Garnish with parsley. Serve warm with your favorite dippers.