Prepare the Crust:

• In a large bowl, whisk together the flour and salt.
• Add the cold butter cubes and use a pastry cutter or your fingers to work the butter into the flour until the mixture resembles coarse crumbs.
• Gradually add ice water, one tablespoon at a time, mixing until the dough just comes together. Form into a disk, wrap in plastic, and refrigerate for at least 30 minutes.

Preheat the Oven:

• Preheat your oven to 375°F (190°C).

Prepare the Filling:

• In a large skillet, heat the olive oil and butter over medium heat.
• Add the chopped onion, red bell pepper, celery, and garlic. Sauté for about 5 minutes until the vegetables are softened.
• Sprinkle in 2 tablespoons of flour and stir for 1-2 minutes to form a light roux.
• Gradually pour in the white wine (if using) and then the seafood or chicken stock, stirring continuously until the sauce thickens slightly.
• Stir in the heavy cream, lemon juice, Old Bay seasoning, paprika, salt, and pepper. Allow the mixture to come to a gentle simmer.
• Add the shrimp and cook for 3-4 minutes, or until they turn pink and opaque. Remove the skillet from heat.

Assemble the Pie:

• Roll out the chilled dough on a lightly floured surface. Carefully line a 9-inch pie dish with the dough, pressing it evenly into the bottom and sides.
• Pour the shrimp filling into the crust, spreading it out evenly.
• Roll out the remaining dough to cover the pie. Trim any excess dough, then crimp the edges to seal.
• Brush the top crust with a beaten egg (egg + water mixture) and cut a few small slits to allow steam to escape.

Bake:

• Place the pie in the preheated oven and bake for 35-40 minutes until the crust is golden brown and the filling is bubbly.
• Remove from the oven and let it rest for 10 minutes before serving. Garnish with chopped fresh parsley.