Preheat the oven to 400°F (200°C).

In a large skillet over medium heat, melt the butter. Add the diced onion and minced garlic and sauté until softened, about 3–4 minutes.

Sprinkle the flour over the softened onions and garlic. Cook, stirring, for about 1 minute to form a light roux.

Slowly pour in the seafood broth while whisking constantly to avoid lumps. Add the heavy cream and stir until the sauce is smooth and slightly thickened.

Bring to a gentle simmer for 1–2 minutes, then stir in the shrimp, crab meat, mixed vegetables, salt, black pepper, and Old Bay seasoning.

Cook just until the shrimp turn pink and opaque, about 2–4 minutes. Remove from heat.

Transfer the hot filling to a baking dish and spread it evenly.

Drop or arrange the Cheddar Bay biscuit dough over the filling in even portions.

Bake for 25–30 minutes, until the biscuits are golden brown and the filling is bubbling at the edges.

Let the pot pie rest for 5 minutes before serving.