Boil water in a pot and cook the spaghetti according to package instructions until al dente.

In a pan, combine miso paste, soy sauce, sesame oil, and vegetable broth. Stir until smooth and heated through.

Drain the pasta and add it to the sauce. Toss to combine and heat for an additional minute.

Serve the miso pasta topped with chopped scallions and toasted sesame seeds.