In a large pot, heat 2 tablespoons of sesame oil over medium heat. Add 2 minced garlic cloves and 1 tablespoon of grated ginger, sautéing for about 1 minute until fragrant.

Pour in 4 cups of chicken or vegetable broth, 3 tablespoons of soy sauce, and 1 tablespoon of rice vinegar, and bring to a gentle simmer for 5-10 minutes.

Add 10-12 frozen potstickers into the broth, cooking for about 5-7 minutes until they float and are fully heated through.

During the last 2-3 minutes, stir in 1 cup of sliced mushrooms and 1 cup of fresh spinach. Allow to soften.

Taste the broth, adjusting seasoning with salt, pepper, and chili oil or red pepper flakes. Simmer for another minute.

Ladle the soup into bowls, garnishing with chopped green onions and a drizzle of sesame oil. Serve immediately.