1In a large pot of boiling, salted water, cook thin noodles for 6 to 8 minutes or thicker noodles for 10 to 12 minutes. Drain well and return to the hot pot. Cover and keep warm.
2Meanwhile, in a large straight-sided skillet, combine the mushrooms, scallions, sake and soy sauce. Bring to a boil over med-high heat. Reduce heat to low. Add fish fillets. Cover and remove from heat. Let stand for 10 minutes. *Note - depending on the size of your fish, you may have to put the pot back on the burner to finish cooking the fish.
3In a medium saucepan, heat miso broth. Using tongs, divide the noodles into 4 soup bowls, ladle broth into soup bowls and top with tilapia. Top with any of the optional additions. Enjoy!