In a large bowl, mix the flour and salt together. Add the cold butter pieces and use your fingers or a pastry cutter to cut the butter into the flour until the mixture resembles coarse crumbs.
Gradually add the water, a little at a time, and mix until the dough comes together. Knead the dough on a floured surface until smooth. Wrap it in plastic wrap and refrigerate for at least 30 minutes.
In a large skillet, cook the ground beef over medium heat until browned. Add the onion, bell pepper, garlic, cumin, paprika, oregano, salt, and pepper. Cook until the vegetables are softened.
Remove the skillet from heat and stir in the chopped olives and hard-boiled eggs. Let the filling cool completely.
Preheat the oil in a deep frying pan or pot to 350° F (175° C).
On a lightly floured surface, roll out the dough to about 1/8-inch thickness. Cut out circles using a round cookie cutter or a glass.
Spoon a small amount of the filling onto one half of each dough circle. Fold the other half over the filling and press the edges together to seal. You can use a fork to crimp the edges for a decorative touch.
Fry the empanadas in the hot oil for about 3-4 minutes per side, or until golden brown. Remove them from the oil and let them drain on paper towels.
Serve the empanadas warm with salsa or chimichurri sauce.
