1. For the empanada dough: Sift the flour and salt into a large bowl. Cut in the butter using a pastry blender or your fingers until it resembles coarse meal with some pea-size pieces.
2. Mix the egg, water, and vinegar in small bowl. Use a fork to stir the wet ingredients into the dry, until just incorporated and shaggy. Turn the mixture onto a lightly floured surface, gather it together, and then knead just until the dough comes together. Form into a flat disk, wrap in plastic wrap, and chill for at least 1 hour.
3. For the picadillo: Heat the olive oil in a large skillet over medium heat. Saute the onion and garlic until browned, about 7 minutes. Turn the heat to medium-high, add the beef, and cook thoroughly, breaking it up with a wooden spoon, about 10 minutes. Stir in the tomato paste, chipotle puree, adobo, and salt and pepper to taste. Cool before assembling the empanadas.
4. Preheat the oven to 375 degrees F, or heat oil in a heavy pot to 350 degrees F. Lightly flour a cutting board and roll the cold dough into a circle about J inch thick. Cut the dough into 7- to 8-inch disks. Paint half of 1 disk with some egg white. Place a scant 1/4 cup picadillo in the center and fold the dough over to form a half-circle. Crimp the edges closed with a fork. Repeat with the remaining dough and filling. Paint the tops of the empanadas with egg white. (Or make mini empanadas with 4- to 41/2-inch circles and J cup of the filling. Adjust the cooking time accordingly.) Bake the empanadas on rimmed baking sheets until golden brown, about 45 minutes, or deep-fry for 3 minutes. Serve.
From Guy Fieri's More Diners, Drive-Ins and Dives book. Adapted from a recipe courtesy of Chef Michael Young of Valencia Luncheria.