Start this recipe by preparing the filo pastry cups. Grease a muffin tin with the melted butter. Cut the filo into 6cm squares, and place a piece into each muffin hole. Brush the filo with melted butter and place another piece of filo on top to form a cup. Bake the filo cups in the oven at 200`c for about 15 minutes, or until they are golden brown. Remove the cups from the oven and start to prepare the meat. Cut the beef fillet into very small strips and place in a bowl. Add in all the ingredients for the spicy coating and mix well to evenly coat the beef strips. In a large pan or wok, heat up the oil and quickly fry the spicy beef strips. Remove them from the pan, add in the sliced spring onions and stir-fry for just a minute. Put the cooked beef strips back into the pan and add in the rice wine or sherry, soy sauce, cashew nuts and fresh coriander and season with the sea salt. Continue to stir-fry for just 1 minute before taking the pan off the heat. Place the filo cups on a serving plate and fill each one with a tablespoonful of the beef and cashew nut stir-fry. Serve immediately.