In a hot pan add the beef and seal over high heat then simmer aprox 5 min until cooked. Remove from pan let cool one min and slice in one inch thick pieces.

In the same pan and using the juices of the beef add the water, sake, soy sauce, fresh ginger and season with salt pepper. Bring to a boil and then simmer for 10 min. This will be the broth of the soup.

In a frying pan add the beef and cook in one tablespoon olive oil, add the mushrooms, green onion and half a cup of the broth. Cook for 1-2 minutes.

Add the udon noodles to the broth over medium heat for about 1 min, then add beef and veggies. Remove the ginger slices and serve while hot.