Preheat oven to 400°.
Mix the flours and salt. Rub the butter into flour using hands until the butter pieces are the size of peas. Whisk the liquids together (egg, water and vinegar) and add to flour mixture. Stir the mixture together until it forms a ball. Wrap with plastic and let it chill for 1 hour while you roast the vegetables.
For the vegetables: mix all remaining ingredients in a large bowl, then bake in a roasting pan at 400° for 35 to 45 minutes. Let them cool.
Lightly flour flat surface and roll out the dough thinly to form a large sheet and cut into twelve 5-inch circles. Place circles on parchment-lined baking sheets. Add a spoonful of roasted vegetables to the center of each circle. Fold the top edge to the bottom edge to form half-moon pies. Crimp the edges. Brush each empanada with egg wash. Bake until golden brown, rotating sheets halfway through, 30 to 40 minutes.