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

Sprinkle flour over the sautéed vegetables and cook for 1-2 minutes to eliminate any raw flour taste. Gradually add broth and heavy cream, whisking until smooth. Stir in paprika and Old Bay seasoning, then simmer for about 5 minutes until thickened.

Gently fold in shrimp, crab meat, frozen peas, and chopped parsley. Cook just until the shrimp turns pink, then remove from heat, allowing the mixture to cool slightly.

In a mixing bowl, combine flour, baking powder, garlic powder, and salt. Stir in shredded cheddar cheese. Then, add melted butter and buttermilk, mixing until just combined; overmixing can lead to tough biscuits.

Preheat oven to 375°F (190°C). Pour the seafood filling into a greased baking dish. Drop spoonfuls of biscuit dough over the filling, making sure to cover most of the surface. Brush the tops with melted butter for a golden finish.

Place in the oven and bake for 25-30 minutes. You'll know it's done when the biscuits are golden brown and the filling is bubbling. If the biscuits brown too quickly, cover them loosely with foil.

Once baked, let it cool for about 5 minutes before serving to allow flavors to settle. Garnish with extra parsley or cheese if desired for an added touch.