In a large mixing bowl, combine the flour and salt.
Add the diced butter and lard to the bowl.
Use your fingertips to rub the butter and lard into the flour until the mixture resembles coarse breadcrumbs.
Gradually add the cold water, mixing until the dough comes together.
Knead the dough lightly, then wrap it in plastic wrap and refrigerate for at least 30 minutes.
In a large bowl, combine the diced beef, potatoes, turnip, and onion.
Season with salt and black pepper to taste.
Preheat your oven to 400°F (200°C).
Divide the chilled dough into 6 equal portions.
On a lightly floured surface, roll each portion into a round about 8 inches (20 cm) in diameter.
Place a generous portion of the filling on one half of each dough round.
Dot the filling with small pieces of butter.
Brush the edges of the dough with a little water, then fold the other half over the filling to create a half-moon shape.
Press the edges together firmly to seal, then crimp the edges decoratively.
Place the pasties on a baking sheet lined with parchment paper.
Brush the tops with the beaten egg.
Bake in the preheated oven for 45-50 minutes, or until the pastry is golden brown and the filling is cooked through.
Allow the pasties to cool slightly before serving.
Enjoy your meal!