Boil vermicelli (careful not to squash). In a pan heat butter and gently fry the onion, cut into crescents. Then add grated carrot and chopped celery. Pour beaten eggs, mixed with chopped green onions. Stir until the eggs become crumbs. If necessary add a little more butter. Add noodles and stir, adding broth and soy sauce. Stir with a spoon until a homogenous and uniform distribution of vermicelli in vegetables. Sprinkle with coarsely chopped coriander and serve.