In a bowl, combine the flour and salt. Cut in the cold butter until the mixture resembles coarse crumbs.
Gradually add cold water, mixing until the dough comes together. Wrap in plastic wrap and refrigerate for at least 30 minutes.
In a skillet over medium heat, cook the ground beef until browned. Drain excess fat if necessary.
Add the chopped onion, bell pepper, and minced garlic. Sauté until softened.
Stir in the tomato paste, paprika, cumin, salt, and black pepper. If the mixture seems dry, add water as needed. Cook for a few more minutes. Remove from heat and let cool.
Preheat the oven to 375°F (190°C).
On a floured surface, roll out the dough to about 1/8 inch thick. Cut out circles (about 4-5 inches in diameter).
Place a spoonful of the beef filling on one half of each circle. Brush the edges with the beaten egg to help seal. Fold over and press edges with a fork to seal.
Place the empanadas on a baking sheet lined with parchment paper. Brush the tops with any remaining beaten egg.
Bake for 20-25 minutes or until golden brown.
Let cool slightly before serving. Enjoy with your favorite dipping sauce.