1. Combine flour, salt and butter in food processor; pulse until flour mixture resembles wet sand. Add egg yolk and milk in 3 additions, pulsing after each, until dough clumps form.
2. Divide dough into 3 discs; wrap and refrigerate 30 minutes.
1. Melt butter in medium skillet over medium heat. Add onion and cook, 8 minutes, until soft. Add ground beef, paprika, chili powder and cumin. Cook, stirring to break up clumps of meat until meat is cooked through, 10 minutes. Let cool slightly; stir in olives, oregano and green onions. Set aside to cool.
2. Roll dough out on a lightly floured surface into a thin sheet. Cut into 4-inch rounds, using a cutter or by tracing with a knife around a small plate.
3. Preheat oven to 400 degrees. Add a spoonful of filling to the center of each round. Brush the edges with egg white. Fold over and seal edges with your fingers. Transfer empanadas to baking sheet; brush tops with remaining egg white mixture. Bake for 25-30 minutes or until golden on top.
Serve warm with Goya Salsa Verde or Goya Pico de Gallo Salsa.