Heat olive oil in a large skillet over medium-high heat. Add ground beef and cook, breaking it up with a spoon, until browned and no longer pink. Drain off any excess fat.

Add chopped onion, garlic, and red bell pepper to the skillet with the beef. Sauté for 5-7 minutes, until vegetables soften.

Stir in tomato sauce, chopped green olives, golden raisins (if using), ground cumin, smoked paprika, dried oregano, and cayenne pepper (if using). Season generously with salt and pepper.

Reduce heat to medium-low, cover, and simmer for 10-15 minutes, allowing the flavors to meld. Remove from heat and let cool completely. This is crucial for easy assembly. Stir in chopped hard-boiled eggs (if using) and fresh parsley once cooled.

In a large mixing bowl, whisk together flour and salt. Add the very cold, cubed butter. Using a pastry blender, your fingertips, or a food processor, cut the butter into the flour until the mixture resembles coarse crumbs with some pea-sized butter pieces remaining.

Gradually add ice water, 1 tablespoon at a time, mixing until the dough just comes together. Do not overmix. The dough should be shaggy but hold together when pressed.

Divide the dough into two equal discs. Flatten each disc, wrap tightly in plastic wrap, and refrigerate for at least 30 minutes, or up to 2 hours. This chilling step is essential for a flaky crust.

Preheat oven to 400°F (200°C). Line two baking sheets with parchment paper.

On a lightly floured surface, roll out one disc of chilled dough to about 1/8-inch thickness. Using a 3.5-4 inch round cookie cutter or the rim of a glass, cut out circles. Re-roll scraps gently and cut more circles until all dough is used.

Place about 1-2 tablespoons of the cooled beef filling in the center of each dough circle. Be careful not to overfill.

Lightly moisten the edges of the dough circle with water using your finger. Fold one half of the dough over the filling to meet the other edge, forming a half-moon shape. Press the edges firmly to seal.

Crimp the edges with a fork or use a traditional "repulgue" (decorative edge) technique to seal them completely. Place the assembled empanadas on the prepared baking sheets.

In a small bowl, whisk together the large egg and 1 tablespoon of water to make an egg wash. Brush the tops of the empanadas with the egg wash for a golden, shiny finish.

Bake for 20-25 minutes, or until the crust is golden brown and flaky. If baking multiple sheets, rotate them halfway through.

Remove from oven and let cool slightly on the baking sheets before serving.