For the veggies and mushrooms (if using), sauté them in a pan with some oil until cooked. Season with some salt, to taste. Set aside or mix with the the noodles later on.
Heat a pot of water. Once it boils, add in the noodles. Cook until chewy and then drain the water.
While the noodles are cooking, heat a pan. Add 1/4 cup oil. Leave to heat on medium low heat. Add in the white chopped scallions first. Leave to cook over low heat for 3-4 minutes or until lightly brown, so as not to burn them. Add in the green part of the scallions. Mix well and then cook for another 3-4 minutes until lightly brown. Add in the sesame seeds and then mix.
Add the cooked noodles into the scallion oil. In a small bowl, mix soy sauce and sugar until sugar is diluted. Add soy sauce mix into the noodles. Feel free to add more soy sauce to taste. Add in the dark soy sauce (if using) for colour. Mix well and then leave to cook for a few more minutes. Enjoy while hot!