Heat a large pot over medium heat and add 1 tablespoon of sesame oil. Sauté 6 minced garlic cloves and 2 inches of sliced ginger until fragrant, about 2-3 minutes. Place 4 chicken thighs skin-side down in the pot and sear until golden brown, approximately 5 minutes. Pour in 6 cups of chicken stock, 1/4 cup soy sauce, 2 tablespoons mirin, and 2 tablespoons miso paste, stirring to combine. Bring to a simmer and let it cook for 45-60 minutes, skimming off any foam that rises to the surface.

While the broth simmers, fill a small saucepan with water and bring it to a rolling boil. Gently add 4 eggs to the boiling water using a slotted spoon and cook for 6-7 minutes for a soft center. Once cooked, transfer the eggs to an ice bath to stop the cooking process for about 5 minutes. After cooling, peel the eggs and set them aside for later assembly.

In a medium pot, bring water to a boil and add 4 servings of ramen noodles, cooking according to the package instructions, typically around 4-5 minutes. Once the noodles are al dente, drain them and rinse under cold water to prevent overcooking and stickiness.

Next, slice 1 cup of shiitake mushrooms and chop 2 scallions, setting them aside. In a separate pot, blanch 1 cup of spinach in boiling water for about 1 minute until bright green, then immediately drain and rinse under cold water to maintain its color.

Once your broth is rich and your toppings are ready, distribute the cooked noodles evenly into serving bowls. Ladle the hot chicken broth over the noodles, ensuring each bowl is filled generously. Arrange the toppings artfully on top, including halved soft-boiled eggs, sliced mushrooms, blanched spinach, corn, chopped scallions, and optional nori sheets.

Your homemade chicken ramen is now ready to be enjoyed! Serve the bowls hot, encouraging slurping for an authentic experience.