Baked Beef Empanadas

Name: Baked Beef Empanadas
Ingredients: 2 tablespoons vegetable oil; 2 cups chopped white onion; 1/3 cup chopped scallion; 1/3 cup chopped red bell pepper; 1/3 cup chopped green bell pepper; 4 cups bite-sized beef chuck pieces (about 1 1/3 pounds); 1/3 cup canned tomato sauce; 1/3 cup chopped pitted olives (optional); 1 chopped hard boiled egg (optional); 1/2 tablespoon dried oregano; 1 teaspoon paprika; 1 teaspoon ground cumin; 1 pinch salt (to taste); 1 pinch black pepper (to taste); 15 empanada dough sheets ((I use Goya brand)); 1 egg; 1 tablespoon water (plus more sealing empanadas)