In a large skillet, melt 2 tablespoons of butter and 2 tablespoons of olive oil over medium heat. Add chopped onion, minced garlic, diced carrots, diced celery, and sliced mushrooms. Sauté for 5-6 minutes until softened, stirring occasionally.

Sprinkle 1/4 cup of flour over the sautéed vegetables, stirring for 1-2 minutes. Gradually pour in 2 cups of broth and 1 cup of heavy cream, whisking until smooth. Bring to a simmer and season with paprika, Old Bay seasoning, salt, and pepper. Cook for about 5 minutes.

Gently fold in 1 cup of chopped shrimp, 1 cup of crab meat, 1/2 cup of frozen peas, and 2 tablespoons of chopped fresh parsley. Cook for an additional 3-4 minutes, then remove from heat.

In a mixing bowl, combine 2 cups of flour, 1 tablespoon of baking powder, 1 teaspoon of garlic powder, and 1 teaspoon of salt. Stir in 1 cup of shredded cheddar cheese, followed by 1/2 cup of melted butter and 3/4 cup of buttermilk. Mix until just combined.

Preheat your oven to 375°F (190°C). Grease a 9x13-inch baking dish, then pour the seafood filling in. Drop mounds of biscuit dough over the filling, brush with melted butter, and sprinkle with parsley. Bake for 25-30 minutes.