Mix the salt and flour together, and then cut in the shortening.
Mix the egg, cold water, and vinegar. Add to flour mixture, and knead to pull dough together. Don't overwork it.
Peel and core apples.
Divide dough into 8 equal portions, about .22# each.
Roll one portion of dough into a very thin disc. Place apple on this disc, and fill core hole with about 2 teaspoons of the sugar and cinnamon mixture. Top with a tablespoon of butter, and fold dough around the apple to seal.
Butter a baking dish big enough to hold the apples without them touching.
Place wrapped apples in the baking pan, making sure the apples don't touch one another.
Preheat oven to 400F.
Mix the sauce ingredients and pour into pan with the apples.
Bake at 400F for about an hour. If you have any cinnamon sugar left over, you can sprinkle it over the dumplings about 10 minutes before they're done. If the sugar doesn't melt, don't worry, it will when you baste the dumpling with the hot sauce. Start watching the dumplings after about 40 minutes in case your oven cooks faster.