Up to 4 hours in advance of cooking, soak bean thread noodles in warm water, ensuring all noodles are submerged.
In a pan on medium heat, add sliced onions to start.
While onions are getting started, mix together the sauce by adding sugar, soy sauce, water, chicken bouillon, and sesame oil.
Add diced mushrooms to pan and stir, cooking until onions and mushrooms start wilting.
Add in your greens on top without stirring.
Drain noodles and add on top of the other vegetables.
Pour sauce over noodles and put lid on the pan.
Allow noodles and vegetables to steam for another 5-10 minutes. Remove lid halfway to gently toss, and continue cooking covered until noodles are completely done.
Gently toss green onions throughout noodles and serve hot or at room temperature!