1. Make the meatballs:

In a large bowl, mix together all meatball ingredients until just combined. Roll into small, bite-sized meatballs (about 1 inch). Heat a large pot or Dutch oven over medium heat with a drizzle of olive oil. Sear the meatballs in batches until browned on all sides (they don't need to be fully cooked). Remove and set aside.

2. Sauté the aromatics:

In the same pot, add the onion, garlic, carrot, and celery. Sauté for 3-4 minutes until softened and fragrant.

3. Simmer the soup:

Add the broth and bring to a gentle boil. Stir in the orzo and return the meatballs to the pot. Simmer for 10-12 minutes, until the orzo is tender and the meatballs are cooked through.

4. Prepare the creamy base: In a small bowl, whisk together tahini, miso paste, and water until smooth.

5. Finish the soup:

Reduce the heat to low. Stir the tahini-miso mixture into the soup, followed by the chopped spinach and lemon juice. Simmer for 2-3 minutes until the spinach is wilted and the broth is creamy.

6. Serve:

Ladle the soup into bowls and garnish with fresh dill or parsley. Serve with lemon wedges on the side for extra brightness.