Prepare Filling: Blitz the chorizo in a food processor into a paste. Sauté diced onion and minced garlic in olive oil until fragrant, then add the chorizo and beef. Cook until browned, stirring in seasoning and tomato paste. Let it simmer for 15 minutes. Cool completely.

Make Dough: Blitz cold, unsalted butter, flour, and salt in a processor until crumbly. Add the egg yolk and warm milk, mixing until a dough forms. Chill the dough for 30 minutes.

Roll and Cut: On a floured surface, roll out the chilled dough to about 3mm thick. Using a cutter, cut out 15cm rounds. Keep the dough covered to prevent it from drying out as you work.

Assemble Empanadas: Place a spoonful of the cooled filling in the center of each round. Optionally, sprinkle in some green olives and pieces of hard-boiled egg. Fold over the dough and press the edges together to seal, crimping with a fork if desired.

Bake: Preheat your oven to 220°C (425°F). Brush the empanadas with beaten egg yolk for a golden finish, then place them on a baking sheet. Bake for about 20 minutes, or until they are golden brown.

Serve: Enjoy these delicious beef empanadas hot from the oven, paired with dipping sauces like chimichurri or a zesty Empanada sauce.