In a large pot, heat 2 tablespoons of sesame oil over medium heat until shimmering. Add 3 minced garlic cloves and 1 tablespoon of grated ginger, sautéing them for about 1 minute until fragrant. Pour in 4 cups of chicken or vegetable broth, bringing it to a gentle simmer. Stir in 2 tablespoons of soy sauce and 1 tablespoon of rice vinegar, allowing the mixture to simmer for 5-10 minutes for a rich broth.

Once the broth is ready, gently add 12-16 frozen potstickers to the pot. Cook for 5-7 minutes until the potstickers float to the surface, indicating they are heated through. During the last 2 minutes of cooking, toss in 1 cup of sliced mushrooms and 2 cups of fresh spinach to infuse freshness and color, stirring well to combine.

After the potstickers and vegetables have cooked, taste the soup and adjust the seasoning. Add salt and pepper as needed, keeping in mind that the broth may contain salt. For an extra kick, drizzle in some chili oil or sprinkle red pepper flakes according to your spice preference, stirring to integrate the flavors thoroughly.

Ladle the steaming Potsticker Soup into bowls, ensuring a balanced portion of broth, potstickers, and vegetables in each serving. Garnish with 2-3 tablespoons of chopped green onions for color and a hint of onion flavor. For a finishing touch, drizzle a little more sesame oil over the top to enhance the soup's richness, and then enjoy your comforting creation!