Heat 15 ml of sesame oil in a large pot or Dutch oven over medium heat. Add the grated ginger and minced garlic, sautéing until fragrant, about 1-2 minutes.

Pour in the chicken broth and add the dried shiitake mushrooms. Bring the broth to a gentle simmer and let it cook for 10 minutes, allowing the mushrooms to rehydrate and infuse the broth with flavor.

Discard the woody stems from the rehydrated shiitake mushrooms and thinly slice the caps. Return the sliced mushrooms to the broth.

Add the instant ramen noodle cakes to the simmering broth. Cook according to package directions, typically 3-5 minutes, until the noodles are tender.

Stir in the baby spinach, sliced scallions, soy sauce, toasted sesame oil, and chili garlic sauce (if using). Cook for another minute until the spinach is just wilted.

Ladle the noodle soup into serving bowls. Top with halved soft-boiled eggs and toasted sesame seeds, if desired.