Pre-heat oven to 450 °F (235 °C)
Season the pork with a teaspoon of salt, a teaspoon of pepper and a pinch of oregano.
Place in a small pot and add the onion, vinegar and enough water to cover it.
Cook over medium heat until the meat is very tender and flaky, adding more water during the process if it should need it.
Once the meat is cooked, let the remaining water evaporate almost entirely (do not let the meat get too dry!)
Using two forks shred the pork.
Core and dice the apples. Add to the meat and the onions from cooking.
Using a potato masher mash the apples a little bit (otherwise the sharp corners of the dice would poke holes in the dough disks).
Season with salt and pepper to taste.
Should the filling be too dry, add two tablespoons of milk and one tablespoons of flour and mix well (flour and milk not included in the list of ingredients).
Reserve.
Use two tablespoons of oil to oil a baking tray.
In a mixing bowl mix flour, salt and baking soda.
Add the remaining oil.
Add the milk.
Mix until all the ingredientes are well incorporated.
Knead lightly until the dough is smooth and elastic.
If the dough is too dry add more milk by the teaspoons.
If the dough is too shaggy add more flour by the tablespoons.
Wrap in plastic film and let it rest at room temperature for at least 10 minutes.
Mix yolk and water and whisk until they are well-mixed.
Remove dough from the film and divide the ball in halves, then again until you have 16 balls.
Roll out the balls with a rolling pin until it is about 3/32" thick (about 2 mm).
Add a tablespoon of the filling in the center and fold over.
Cut a half-disk (3.5" diameter) with a cup or whatever you have. Remove the excess dough.
Press the edges with a fork and place on the baking tray.
Paint the pasties with the egg wash.
Bake until they are golden brown (10 - 15 mins).
Cool for a couple of minutes on a wire rack
