Mix rosemary, sage, salt, pepper, sugar, garlic, and chicken stock together. Add chicken stock and spices to celery onions and spinach. Cook for 5 minutes on low to medium heat, stirring occasionally.
Remove completely from the heat and add the cheese and bread. Mix until cheese is melted liquid is absorbed into the bread and stuffing looks consistent throughout. Finish by drizzling Roasted Walnut Oil on top (optional). Add more bread if needed to make stuffing drier.