Combine flour and salt: In a large bowl, combine flour and salt.

Cut in butter: Cut in the cold butter until the mixture resembles coarse crumbs.

Add water: Gradually add ice water, mixing until the dough comes together.

Form dough: Shape the dough into a disc, wrap in plastic wrap, and refrigerate for at least 30 minutes.

Cook ground beef: In a large skillet over medium heat, cook ground beef until browned. Drain off any excess grease.

Sauté vegetables: Add the onion and garlic to the skillet and sauté until softened.

Add ingredients: Stir in the black beans, diced tomatoes, chili powder, cumin, salt, and pepper. Simmer for 5-10 minutes, or until the flavors have combined.

Roll out dough: On a floured surface, roll out the dough to about 1/8 inch thickness. Cut into circles using a 3-inch cookie cutter.

Fill empanadas: Place a spoonful of the beef filling in the center of each circle. Fold the dough over and pinch the edges firmly to seal.

Brush with egg wash: Beat the egg and water together in a small bowl. Brush the tops of the empanadas with egg wash.

Bake: Bake in a preheated 400°F (200°C) oven for 20-25 minutes, or until golden brown and crispy.

Optional toppings: You can serve empanadas with your favorite dipping sauce, such as salsa, guacamole, or sour cream.