Soak sweet potato noodles in warm water until softened
Slice beef thinly and marinate with soy sauce, sugar, garlic, and sesame oil
Cut spinach, carrots, onions, mushrooms, and bell peppers into thin strips
Blanch spinach briefly, then squeeze out excess water and season with sesame oil, salt, and garlic
Cook noodles in boiling water until tender, then drain and cut into shorter lengths
Stir-fry each vegetable separately with a little oil and salt
Cook the marinated beef until done
Mix noodles with soy sauce, sesame oil, sugar, and minced garlic
Add the cooked beef, vegetables, and spinach to the noodles
Toss everything together until well combined
Sprinkle sesame seeds on top
Serve warm or at room temperature