Melt butter in a large Dutch oven or skillet over medium heat. Add the onion, carrots, and celery and cook until softened, about 5-7 minutes. Stir in the garlic and cook for another minute until fragrant.

Sprinkle the flour over the vegetables and stir continuously for 1 minute to cook out the raw taste.

Slowly whisk in the chicken or seafood stock until smooth. Then, whisk in the heavy cream.

Bring the mixture to a simmer and let it cook for 3-5 minutes, stirring occasionally, until it has thickened.

Stir in the Old Bay seasoning, dried parsley, salt, and pepper. Remove from the heat.

Gently fold in the shrimp, scallops, crab meat, and frozen peas. Pour the filling into a 9x13 inch baking dish.

Preheat oven to 400°F (200°C). In a large bowl, whisk together the flour, baking powder, sugar, garlic powder, and salt.

Cut in the cold, cubed butter using a pastry blender or your fingers until the mixture resembles coarse crumbs. Stir in the shredded cheddar cheese.

Pour in the cold buttermilk and stir until just combined. Do not overmix.

Drop spoonfuls of the biscuit dough evenly over the seafood filling in the baking dish.

Bake for 20-25 minutes, or until the filling is bubbly and the biscuit topping is golden brown and cooked through.

While the pot pie is baking, whisk together the melted butter, garlic powder, and dried parsley for the topping.

As soon as the pot pie comes out of the oven, brush the garlic herb butter generously over the hot biscuits. Let rest for 5-10 minutes before serving.