Marinate Noodles: Drain the noodles and rinse with hot water. Place them in between paper towels and dry them out as much as possible. Transfer semi-dry noodles to a bowl and add the soy sauce, sriracha and rice wine vinegar. Stir and coat all noodles and place in fridge for 1-4 hours.
Make the soft boiled egg: Bring a small pot of water to a gentle simmer. Cook for 6 minutes. Remove and place in a bowl of cold water or an ice bath to stop cooking.
Heat a skillet with butter and cook chicken thigh in the skillet. Allow to cook until skin is crispy, about 4 minutes per side. Once cooked remove and allow to rest for 10 minutes prior to cutting.
Keep the skillet off to the side to use for noodles and mushrooms.
Once the noodles have marinated long enough, drain off the excess marinade and transfer to the same skillet the chicken was cooked in. Turn the burner to high heat and allow the noodles to cook for 3-5 minutes until all the marinade from the noddles has cooked off/reduced.
Transfer the cooked noodles to a large serving bowl.
Add the mushrooms to the skillet and cook for 2-3 minutes, or until preferred done-ness. Transfer to bowl with noodles.
Cut the cooked thigh into 4-5 pieces and place in the bowl with the noodles. Remove the egg from the ice bath and gently peel off the shell. Place in the center of the bowl.
Garnish with sesame oil, and scallions. Top with sesame seeds, if desired. Enjoy!