Step 1Soak the mushrooms in cold water for about 1 hour.
Step 2Cook the noodles in boiling water for about 4 to 5 minutes. Immediately drain and thoroughly rinse in cold water. (Before cooking, cut the noodles with scissors into 6- or 7-inch lengths for easier eating.)
Step 3Squeeze the liquid from the mushrooms and slice. Heat 4 tablespoons vegetable oil in a skillet. Add the mushrooms, beef, 2 cloves of the minced garlic, 1 tablespoon soy sauce, 1 teaspoon sesame oil, 1 teaspoon sesame seeds and saute until the beef is cooked (about 3 to 4 minutes). Remove from heat; set aside.
Step 4In boiling water, blanch the spinach about 2 minutes. Squeeze the water from the spinach and cut the compressed mass in quarters and separate the pieces. In a bowl, combine the spinach, 2 cloves minced garlic, 1 teaspoon salt, 1 teaspoon sesame oil and 1 teaspoon crushed sesame seeds and mix. Set aside to marinate.
Step 5Heat the remaining 3 tablespoons vegetable oil in a skillet over medium-high heat. Add the onions, carrots, green pepper and 1 teaspoon salt and saute for about 3 to 4 minutes. Add the green onions and stir-fry for about 1 minute more. Remove from the heat and set aside.
Step 6In a large bowl, thoroughly combine the noodles, beef mixture, spinach, onion mixture, one-half cup soy sauce, 2 tablespoons sesame oil, 1 tablespoon whole toasted sesame seeds and sugar to taste. Serve warm, sprinkled with whole sesame seeds, if desired.