Preheat the oven to 400°F (200°C).

Melt the butter in a medium saucepan over medium heat. Add garlic, onion, and celery; cook until soft and fragrant, about 5 minutes.

Sprinkle in flour, stirring to form a roux. Cook for about 1 minute, then whisk in seafood stock and heavy cream. Cook until thickened, about 5-7 minutes.

Season with Old Bay seasoning, salt, and pepper. Fold in shrimp and cook until pink, then add lobster and parsley.

In a mixing bowl, combine flour, baking powder, garlic powder, and salt. Cut in cold butter until resembling coarse crumbs.

Stir in cheddar cheese and milk until just combined. The dough should be slightly sticky.

Spoon the seafood mixture into a baking dish. Dollop biscuit dough on top, leaving gaps for steam.

Bake for 20-25 minutes until biscuits are golden brown and filling is bubbling.

Let rest for 5-10 minutes before serving.