Microwave onions, garlic, ginger and oil in a bowl – about five minutes, stirring occasionally. Transfer to a slow cooker.
Stir in broth and mushrooms. Season pork with salt and pepper and nestle into slow cooker.
Cover and cook until pork is fork tender – 7-8 hours on low or 4-6 on high.
Transfer pork to a cutting board, and using two forks, shred the pork into bite size pieces. Skim any fat off the top of the soup.
Stir in the instant ramen noodles, and spinach, cover and let cook for about 8 minutes. Stir in the shredded pork, miso, soy sauce, mirin, and oil and let it set until it’s heated through. Serve.
Sprinkle each bowl with a few green onions and sesame seeds before serving.
