In a large mixing bowl, combine all the flour, salt and baking powder.
Using a pastry cutter, cut the shortening into the flour mix until it looks and feels like breadcrumbs.
Slowly add the water, mixing as you go until a dough starts to come together.
Form the dough into a ball, pressing it together firmly, Wrap in cling film and refrigerate for at least 30 minutes.
To make the filling
Bring a pan of water to the boil and lower in 8 of the eggs. Bring back to the boil and simmer for 6 mins. Drain, then cool under cold water. Peel and set aside.
With your hands, mix together the sausage meat and chopped scallions.
To assemble
Roll out the cold pastry on a well floured surface and cut into 7" circles using a side plate or bowl as a guide. Re-roll the pastry as needed.
Using dampened hands, squash out an eighth of the sausage mix over each of the rounds of pastry, going almost right to the edges. Use a little water to wet the edges of the pastry. Sit a peeled egg in the middle of the sausage, season with a little salt and pepper, then pull the sides up over the egg and seal. Crimp the edges and put onto the baking sheet.
Beat the remaining egg with splash of water to create an egg wash. Brush the pasties with the egg wash and place in the refrigerator for 30 mins.
Preheat the oven to 400ºF. When ready, bake the pasties until nice golden brown, about 25 minutes.
Serve hot with baked beans or cold with piccalili on the side.