Heat olive oil in a large pot over medium heat. Add onion, carrots, and celery. Cook until softened, about 5 minutes.

Add garlic and cook for another minute.

Add chicken pieces and cook until they start to brown, about 5 minutes.

Pour in chicken broth, quinoa, bay leaves, and thyme. Bring to a boil, then reduce heat and simmer for 15-20 minutes, or until quinoa is cooked and chicken is tender.

Stir in spinach and cook until wilted, about 2 minutes.

Remove bay leaves. Add lemon juice and zest.

Season with salt and pepper to taste.

Serve hot, garnished with fresh dill if desired.