Lunar New Year Rice Cake Soup

Sauté onion and garlic in a large pot until fragrant. Add water, kombu, dried shiitake mushrooms, scallions, and celery into the pot and bring to a boil. Simmer for about 40 minutes to an hour. Strain the broth and return it to the pot. Stir in the miso paste. Bring to a boil again and add defrosted rice cakes and sliced shiitake mushrooms. Simmer until the rice cakes are fully cooked and soft, about 5 minutes. Add in the spinach and stir. Ladle into bowls and top with toasted nori sheets and sesame seeds. Enjoy!