1. Place the beef cubes and green onion pieces neatly onto 4 bamboo skewers alternating each as you go. Combine together the marinade mix of soy, Mirin and sugar, and then coat the skewers well.
2. Bring to a boil the dashi, soy, Mirin salt and sugar, then turn down and simmer for 3 minutes. Remove from the heat and set aside.
3. In a pre-heated grill pan cook the skewers with olive oil quickly until medium rare. Place a neat portion of the noodles into each serving bowl and top with a beef skewer. Pour the hot broth over each skewer and finish with the sliced spring onions.