In a large bowl mix the flour and salt well. Cut in the cold butter until crumbs form. Combine water and vinegar, then add 1 tablespoon at a time to the bowl and stir until pastry comes together. Quickly push the mass into a ball, flatten slightly and wrap in foil. Chill at least 1 hour.
To Make the Filling
Mix all filling ingredients in a small bowl.
To Assemble
Preheat the oven to 350°F. Line two baking sheets.
Roll the pastry into a thin (⅛ - ¼ inch) rectangle. With a round cookie cutter cut out circles of about 2 ½ inches in diameter. Spoon about a teaspoon of filling onto half the circles and cover with the other half. Seal the edges with the back of a fork and make three small incisions on top. Lightly brush with egg wash and sprinkle with light brown sugar.
Bake for 20-25 minutes or until golden. Cool on the cookie sheet for 10 minutes, then remove to a cooling rack.