Season the chicken thighs with salt and pepper. In a large pot, heat 1 tablespoon of sesame oil over medium heat. Add the chicken thighs and cook for about 5-7 minutes per side until they are browned and cooked through. Remove from the pot and let them rest, then slice into thin strips.
In the same pot, add the remaining sesame oil, minced garlic, ginger, and sliced red chili pepper. Sauté for about 2 minutes until fragrant.
Pour in the chicken broth and bring to a gentle simmer. Add the soy sauce and chili paste, stirring to combine. Let it simmer for about 5 minutes to develop the flavors.
Add the ramen noodles to the broth and cook according to the package instructions until al dente, typically about 3-4 minutes.
Once the noodles are cooked, add the sliced chicken back into the pot along with the baby spinach. Stir until the spinach wilts, about 1-2 minutes.
To serve, ladle the fiery chicken ramen into bowls. If using, halve the soft-boiled egg and place it on top of each bowl of ramen. Garnish with chopped green onions and sesame seeds.
Notes
Adjust the spice level by varying the amount of chili pepper and chili paste.