Traditionally, this comfort-food stew is made with flash-fried and then long-simmered fish heads. Tilapia fillets make an excellent, quick-cooking substitute.
Prepare noodles according to package directions. Drain and rinse with cold water. Drain. Snip noodles several times with kitchen shears.
Combine 2 cups boiling water and mushrooms in a medium bowl; let stand 20 minutes. Drain mushrooms in a sieve over a bowl; discard mushrooms. Combine mushroom soaking liquid, broth, and next 7 ingredients (through salt) in a Dutch oven. Bring to a boil. Cover, reduce heat, and simmer 20 minutes. Add tilapia; cover and simmer 10 minutes. Stir in noodles and tofu; simmer, uncovered, 5 minutes. Ladle 1 cup soup into each of 8 bowls; sprinkle each serving with 1 1/2 teaspoons green onions.
This is one of our go-to fish dishes. It's fairly easy to make and the flavors are incomparable.