Combine sifted flour and butter in the bowl of a food processor; pulse until crumbly. Add egg and pulse until just combined.
Dissolve salt in warm water. Add gradually to the food processor and pulse until a soft dough ball forms. Place dough ball into a bowl and wrap tightly with plastic wrap. Refrigerate for at least 30 minutes.
Dust a work surface with flour and knead dough for 1 minute. Roll out thinly and cut into rounds; use right away for your favorite sweet or savory empanadas, or freeze for later.
Add a filling of your choice (sweet or savory), seal with water and a fork, brush with egg wash, and bake at 375 until golden.
