Heat the vegetable oil in a 10-inch skillet. Add the onion and sauté for 2 minutes, until the onion turns translucent. Add the ground beef, and brown for about 4 minutes, until the beef is completely cooked. Add the olives, raisins, egg, garlic and season with salt. Stir to combine well, then remove from the heat and cool slightly.
Heat your oven to 350°F. On a floured surface, unfold one of the sheets of the Pepperidge Farm® Puff Pastry, and roll out with a rolling pin so that the folds are no longer visible. Sprinkle a bit of extra flour on the top surface of the pastry for easier rolling.
Use a 5”to 6” round cutter or template to cut out circles from the dough. (We used the lid of a large round plastic yogurt container with excellent results.) If the dough seems too small to yield 4 circles per sheet of puff pastry, simply roll the pastry a bit thinner and wider.
In a separate small bowl, whisk together the raw egg and water. Set aside.
Fill each pastry circle with 2 to 3 tablespoons of the meat mixture. Pinch the edges of the circle together well to seal and form a half moon shape. Place the empanada on a parchment lined baking sheet, and seal the empanadas again by pressing down the pinched edges with the tines of a fork. Once all the empanadas are well sealed, brush the top and edges with the egg mixture.
Bake the empanadas in the oven for 15 to 20 minutes, until they are golden brown. Cool slightly before serving.