Trim any fat from the beef. Mix the ginger with 1 teaspoon of the soy sauce and smooth over both sides of the beef. Cook the noodles according to the directions on the packet. Drain and rinse thoroughly in cold water.
Bring the stock to a gentle simmer with the chilli, garlic and sugar. Cover and cook gently for 5 minutes.
Heat the oil in a small, heavy-based frying pan and fry the beef for 2 minutes on each side. Transfer the meat to a board, cut it in half lengthways and then cut it across into thin strips.
Add the noodles, sugar snap peas, basil and remaining soy sauce to the soup and heat gently for 1 minute. Stir in the beef and serve immediately.