1.Combine the water, stock, ginger and garlic in large saucepan; bring to a boil. Add sambal oelek, fish sauce and sugar; simmer, uncovered, for 1 minute.
2.Meanwhile, place noodles in large heatproof bowl, cover with boiling water; separate with fork, drain. Divide noodles among serving bowls.
3.Place steak in simmering broth; bring to a boil. Pour broth and steak over noodles; top with onion. Serve with bean sprouts, mint and lemon wedges, if desired.