Preheat oven to 400 degrees.

In a large bowl, combine flour, salt, lard, and butter, mixing with your hands until the fat is in pea-size chunks. Slowly drizzle in cold water, stirring, taking care not to make the dough too wet--check by pressing it into a ball, if it doesn't fall apart into dry chunks, it's ready. Add more water a teaspoon at a time if if needed.

Divide the dough into five balls (about 9 oz each). (You can refrigerate the dough up to 24 hours at this point.) Roll the first piece out to a 9-inch circle. Pile the center of the dough with generous layers of potatoes, meat, onion, parsley, suet, and 1 tsp flour. Sprinkle each layer generously with salt and pepper. (I like to make a salt-pepper mixture in a bowl, like they do at Subway.) Using your fingers, moisten the edge of the dough with water and lift the two sides of the pastry to seal on top. Crimp edge with your fingers to hold it together. Place on a sturdy, parchment-lined cookie sheet. Repeat with remaining balls of dough.

Beat the egg and milk together in a small bowl. Brush each pasty with the egg mixture and cut two slits in the top with a sharp knife. Bake 30 minutes, then reduce oven to 350 degrees and continue baking 30 more minutes. Cool on a rack 10 minutes before serving.