In a large pot, heat the sesame oil over medium heat. Add minced garlic and grated ginger, sautéing until fragrant, about 1-2 minutes.
Pour in the vegetable broth and bring it to a gentle simmer.
Add the frozen potstickers to the pot and let them cook for 5-7 minutes, stirring occasionally.
After the potstickers have cooked through, add the sliced mushrooms and chopped bok choy. Cook for an additional 3-4 minutes until the vegetables are tender.
Stir in the soy sauce, and season with salt, pepper, and chili flakes if desired. Remove from heat.
Serve the soup hot, garnished with chopped green onions and fresh cilantro.