For the pastry
Stir the flour and salt together in a large bowl.
Beat water egg, egg white, and vinegar together in a small bowl.
Cut butter into flour mixture. I do this with my hands until it resembles crumbs.
Make a well in the center of the flour and add wet ingredients.
Stir until it forms a smooth dough.
Wrap in plastic and refrigerate for at least one hour or up to overnight.
(It can also be frozen)
For the filling
Sauté onion and bell pepper until translucent and add garlic and cook for 5 minutes longer or until golden.
Add tomatoes and roast beef.
Let simmer until most all of the liquid has evaporated, shredding the roast beef as you stir.
When most of the liquid is gone, remove from heat and let cool.
Assembling the Empanadillas
Remove dough from the refrigerator and cut into 10 equal balls.
Roll each ball into a 6” circle.
Put filling in the center, fold, and seal edges with a fork.
Fry in medium hot oil until golden brown.
Drain on paper towel. Enjoy!