Combine the dry ingredients: Add the flour, salt, and sugar to a large mixing bowl. Whisk them together until evenly distributed.

Cut in the cold butter: Add the cold butter cubes to the flour mixture. Use a pastry cutter or two forks to work the butter into the flour until you have pea-sized pieces throughout. Some larger, flattened butter pieces are ideal for creating flaky layers.

Prepare the wet ingredients: In a small bowl, whisk together the egg, ice cold water, and vinegar.

Bring the dough together: Pour the wet ingredients over the flour mixture. Use a fork to gently stir until the dough starts to clump together in shaggy pieces. Do not overmix; you want visible butter streaks remaining.

Knead briefly: Turn the dough onto a lightly floured surface. Knead it gently just 5 to 6 times until it comes together into a cohesive ball.

Chill the dough: Shape the dough into a flat disc about 1 inch thick. Wrap it tightly in plastic wrap and refrigerate for at least 1 hour.

Roll and cut the discs: Remove the chilled dough and let it sit at room temperature for 5 minutes. Roll it out on a floured surface to about 1/8 inch thickness, rotating the dough frequently to prevent sticking. Use a 5 to 6 inch round cutter to cut circles. Gather scraps gently, re-roll once, and cut additional discs.

Fill and shape your empanadas: Place about 2 tablespoons of your chosen filling in the center of each disc. Fold the dough over to create a half-moon shape and press the edges firmly to seal. Crimp the edges with a fork or create a decorative rope pattern with your fingers.