In a large bowl, combine the flour and cold, cubed butter. Rub the mixture together until it resembles breadcrumbs.
Gradually add cold water, a tablespoon at a time, until the mixture comes together to form a dough. Do not overmix.
Wrap the pastry in plastic wrap and refrigerate for at least 30 minutes.
Preheat the oven to 3750F (1900C).
In a large mixing bowl, combine the diced meat, potatoes, onion, and swede. Season with salt and black pepper.
Divide the pastry into four equal portions and roll each portion into a circle on a floured surface.
Place a portion of the filling on one half of each pastry circle.
Fold the pastry over the filling, crimp the edges to seal, and transfer the pasties to a baking sheet.
Brush each pasty with the egg wash for a golden finish.
Bake for 40-45 minutes or until the pasties are golden brown and the filling is cooked through.
