In a large pot, pour in the chicken or vegetable broth and heat over medium flame until it reaches a gentle simmer.
Once simmering, introduce the soy sauce, miso paste, garlic powder, and ginger powder to the broth. Whisk the mixture well until the miso paste is fully dissolved, ensuring a rich flavor base.
Add the sliced shiitake mushrooms to the simmering broth. Allow them to cook for approximately 5 minutes, or until they are tender and infused with flavor.
Gently crack the eggs into the broth, being careful not to break the yolks. Poach the eggs to your desired doneness—usually about 6-8 minutes for a soft-boiled texture, where the yolk remains slightly runny.
While the broth simmers and the eggs poach, take a separate pot and prepare the instant ramen noodles according to the package instructions. Drain the noodles well once cooked.
When the mushrooms are soft and the eggs are finished poaching, toss in the baby spinach to the broth. Let it cook for about 1-2 minutes, or just until the spinach is wilted and vibrant.
In serving bowls, evenly distribute the cooked ramen noodles as a base. Carefully ladle the hot broth, along with the mushrooms and spinach, over the noodles, filling the bowls generously.
Gently place a poached egg atop each bowl of ramen, ensuring it sits proudly in the center.
Finally, garnish each bowl with a sprinkle of the chopped green onions and a light dusting of sesame seeds to add a delightful crunch.