Combine all pastry ingredients in a food processor and pulse until a soft pastry dough ball forms. Wrap tightly in cling film and chill in the fridge for 20 minutes.
Preheat the oven to 220 C / Gas 7. Cover a baking tray with aluminium foil, brush with vegetable oil and set aside.
For the filling:
In a large saucepan, heat 1 tablespoon of olive oil over medium heat. Add diced eye of round beef and cook until fully browned. Remove from pan and set aside.
In the same saucepan, melt butter over medium heat. Cook and stir the onions, spring onions and red peppers until tender, for 5 minutes. Stir in the beef and cook for an additional 5 to 7 minutes. Season with salt, pepper, cumin and paprika. Stir gently and cook for another 4 minutes.
Remove from heat and stir in chopped hard boiled eggs. Let it cool down completely before filling the empanadas.
Roll the empanada pastry on a lightly floured work surface with a rolling pin to 2mm thickness. Cut with pastry cutter or sharp knife into 10cm circles. Lightly wet the edges with salted water. Add 1 large tablespoon of filling into the centre of each disc then fold the pastry over and seal edges with a fork. Transfer the empanadas to the prepared baking tray.
Bake in preheated oven for 15 minutes, or until golden brown. Remove from the oven and allow to cool just a little before serving.
If you are unable to get the eye of round, substitute with another cut such as rump.