How to Make It
In a small saucepan, combine the water and salt and bring to a simmer. Add the lard and stir until melted. Pour the liquid into a large bowl and let cool to room temperature.
Using a wooden spoon, stir in 4 cups of the flour, 1 cup at a time, until the dough begins to form a ball. Turn the dough out onto a lightly floured work surface and knead, adding the remaining flour as necessary, 2 tablespoons at a time, until a stiff, dry dough forms. Divide the dough into 4 equal pieces, pat them into 1-inch-thick disks and cover with plastic wrap. Chill for at least 1 hour and up to 24 hours.
In a bowl, season the meat well with salt and black pepper. In a large nonstick skillet, melt 1 tablespoon of the lard in the 4 tablespoons of butter. Add the onions and cook over moderately low heat, stirring, until translucent, 8 minutes. Stir in the crushed red pepper, cumin, paprika and the scallion whites and cook, stirring, for 2 minutes. Off the heat, stir in the scallion greens. Season with salt and black pepper and transfer the onion mixture to a large bowl.
Wipe out the skillet and heat 1 tablespoon of the oil in it. Add half of the meat and cook over moderately high heat, stirring, until well browned, about 2 minutes. Using a slotted spoon, transfer the meat to the onions. Wipe out the skillet and repeat with the remaining 1 tablespoon of oil and meat; transfer to the bowl. Add the oregano and remaining 3 tablespoons of lard to the meat and mix well. Season with salt and black pepper. Cover and chill until firm.
Line 2 baking sheets with parchment paper. On a lightly floured work surface, using a lightly floured rolling pin, roll out one piece of dough to a 7-by-14-inch rectangle, about 1/8 inch thick. Using a 3 1/2-inch round cookie cutter, stamp out 6 rounds of dough and transfer them to the prepared baking sheets; save the scraps. Repeat with the remaining 3 pieces of dough. Combine all of the scraps and knead them into a disk. Roll out and stamp out 6 more rounds; transfer to the baking sheet.
Preheat the oven to 350°. Place 1 tablespoon of the meat filling in the center of each dough round. Top with the chopped eggs, olives and small cubes of butter. Using your finger, moisten the rim of each dough round with water and fold the dough in half over the filling to form half moons. Pinch the edges together to seal and crimp decoratively. Bake the empanadas for 20 to 25 minutes, flipping them halfway through baking, until golden. Serve hot.