Cook the potatoes in boiling water for 8 minutes. Remove from water. Once cool enough to handle, peel and cut into cubes. Set aside.
In a large frying pan, melt the butter and saute onion and spring onion until softened. Add the red capsicum, and cook 3 minutes. Add beef mince, and cook and stir until browned. Season with salt, paprika and cayenne pepper.
Remove mince mixture from heat and add potatoes and olives, and mix well. Stir in the chopped hard boiled eggs. Let cool.
Preheat the oven to 220 degrees C. Line baking trays with foil, then grease the foil.
Place the empanada pastry rounds on a flat surface and lightly wet edges with warm water. Put a large tablespoon of cooled filling in the centre of each then fold pastry over and seal the edges by pressing with a fork. Transfer empanadas to baking trays and brush with beaten egg.
Bake in the oven for 15 to 25 minutes, until golden.