In a large skillet over medium heat, melt 4 tablespoons of unsalted butter. Add 1 diced onion, 2 minced garlic cloves, 2 diced celery stalks, and 1 diced bell pepper. Sauté for about 5–7 minutes until the veggies are tender and onions become translucent.

Stir in 1 tablespoon of Cajun seasoning, 1 teaspoon of paprika, 1 teaspoon of thyme, salt, and pepper, cooking for an additional 2 minutes to release the spices' aromas.

Sprinkle 1/4 cup of all-purpose flour over the sautéed vegetables, stirring continuously for about 2–3 minutes to form a roux.

Slowly whisk in 2 cups of seafood stock, followed by 1 cup of heavy cream. Keep stirring until the mixture thickens, approximately 5–7 minutes.

Reduce the heat to low and fold in 1 cup of frozen peas, 1 pound of peeled and chopped shrimp, and 1 cup of fresh lump crab meat. Cook the mixture for about 3–5 minutes.

Preheat your oven to 375°F (190°C). Carefully pour the creamy seafood filling into a large baking dish, spreading it evenly.

Unroll 1 sheet of puff pastry, covering the filling and pressing the edges to seal.

Make several small slits in the crust to allow steam to escape during baking.

Brush the top of the crust with an egg wash made from 1 beaten egg mixed with a splash of water.

Place the assembled pot pie in the preheated oven and bake for 30–35 minutes, or until the crust is golden brown and the filling is bubbling from the vents.

Once baked, remove the Seafood Pot Pie from the oven and let it cool for about 10 minutes before serving.