Melt butter in a skillet over medium heat and sauté the diced onion and garlic until soft and fragrant to create the flavorful base for the seafood filling.
Stir in the flour and cook for about 1 minute, then slowly whisk in the broth and heavy cream. Let it simmer until the sauce thickens into a rich creamy gravy.
Fold in the shrimp, scallops or fish, cheddar cheese, Old Bay seasoning, salt, and pepper. Cook gently for a few minutes until the seafood is tender and coated in the sauce.
In a bowl mix biscuit mix, shredded cheddar, garlic powder, milk, and melted butter until a soft biscuit dough forms.
Spoon the seafood filling into small ramekins or baking dishes, top with spoonfuls of biscuit dough, and bake at 375°F (190°C) for 22–25 minutes until the biscuits are golden and the filling is bubbling.
Serve hot topped with fresh parsley for the ultimate cozy seafood dinner.