Soak the noodles in very warm water until softened, about 10 minutes.
Dissolve the bouillon cubes in 5 cups boiling water. Add half of the sliced green onions and season to taste with more salt and pepper if needed.
Once the noodles are softened, drain them, put into a strainer set in a large bowl and fill the bowl with boiling water. Let sit for 5 seconds, drain and divide the noodles among 4 large soup bowls. Divide the hot broth among the 4 bowls of noodles. Serve immediately with all the additional ingredients on the side. Let each diner design their pho the way they want.