In a large pot, combine the chicken broth, whole milk, white miso paste, soy sauce, sesame oil, minced garlic, and grated ginger. Whisk gently to dissolve the miso paste.
Place the pot over medium heat and bring the broth to a gentle simmer.
Add the sliced shiitake mushrooms to the pot and cook for 3 minutes until slightly softened.
Add the fresh ramen noodles to the pot and cook according to package instructions, about 3 to 4 minutes, stirring occasionally to separate the noodles.
While the noodles cook, bring a small saucepan of water to a boil. Carefully add the eggs and boil for 7 minutes for soft-boiled eggs.
Remove the eggs from boiling water and place them in an ice bath for 2 minutes. Peel and set aside.
Once the noodles are tender, stir in the baby spinach leaves and cook for an additional 1 minute until wilted.
Divide the ramen and broth evenly between two bowls.
Cut the soft-boiled eggs in half and place one half on top of each bowl of ramen.
Garnish each bowl with sliced green onions and toasted sesame seeds.
Serve immediately and enjoy your creamy one pot ramen.