Cheesy Spinach Empanadas

Instructions

1. MAKE THE FILLING: Heat the oil in a large skillet with high sides over medium-high heat.
2. Add the onions and cook, stirring, until softened, about 3 minutes.
3. Add the garlic and cook for 20 seconds.
4. Add the spinach in batches, stirring it in well (it will cook down to fit in the skillet).
5. Cook until there is no liquid left and the spinach is cooked through, 8 to 10 minutes (the spinach will still be moist).
6. Stir in the salt, pepper, and nutmeg.
7. Remove the filling to a bowl and let it cool completely; cover and chill it for 2 hours.
8. Stir in the mozzarella, ricotta, and Parmesan to combine; chill the filling again, covered, until ready to use.
9. ASSEMBLE THE EMPANADAS: After the filling chills, make the dough as directed and let it rest, covered with plastic wrap, for 10 minutes at room temperature.
10. Divide the dough into 28 equal pieces (about 2 ounces/55 g each).
11. Roll each piece into a ball, folding the bottom of the dough onto itself so that the ends are at the bottom and the tops are smooth (the way you'd shape rolls).
12. Place them on a lightly floured baking sheet and cover them with a clean towel; let them rest for 10 minutes.
13. On a well-floured surface, press each ball slightly into a disc.
14. Line a tortilla press with a zip-top freezer bag that has been cut open on three sides so that it opens like a book.
15. Place a disc in the middle of the tortilla press and flatten it into a 5-inch (12-cm) round, about 18 inch (3 mm) thick (or roll it out with a rolling pin).
16. Stack the discs with parchment paper in between to avoid sticking.
17. Line three baking sheets with parchment paper; set them aside.
18. Place 2 heaping tablespoons of the filling in the center of each disc.
19. Fold the bottom of the dough to meet the top of the disc, encasing the filling and forming a half-moon, and press the edges together well.
20. Make 1/2-inch (12-mm) edges by pressing the rims between your fingers using the repulgue method (see Notes).
21. The empanadas can sit at room temperature uncovered for 20 minutes before baking or can be refrigerated for up to 1 hour before baking.
22. BAKE THE EMPANADAS AND SERVE: Preheat the oven to 450F (230C).
23. Place the empanadas on the prepared pans and brush them with the egg wash. Bake the empanadas for 28 to 30 minutes, or until golden (rotate the pans in the oven halfway through baking, back to front and top to bottom, to ensure that all of the empanadas bake evenly).
24. Transfer the empanadas to a cooling rack; let them cool for 10 minutes before serving.