Combine the ground beef, paprika, chili powder, cumin, salt and pepper in a large bowl, mix, and chill until ready to use.
Melt the butter in a large sauté pan,
Add the onions and salt, cook until the onions are soft, about 6-8 min.
Add the meat to the onions and cook on med heat, until no longer pink
Add the chopped eggs and chopped olives.
Let the picadillo cool, and then mix in the green onions and oregano.
To assemble, add a spoonful of the meat mixture on the center of each empanada,
Brush the edges of the empanada with the egg whites, that helps seal the empanada.
Fold the empanada and seal the edges gently with your fingers, and then use a fork to press down and finish sealing.
Lightly brush the top of the empanadas with the egg; for a nice golden color when they bake.
Empanadas can rest in the fridge for about 30 min, until ready to bake.
Preheat the oven to 400 F and bake for 20-25 min, until golden on top.
Serve warm with chimichurri sauce or other dipping sauces.