In a large, heavy-based pan set over medium-high, combine tomatoes, stock powder and 2 cups water and bring to the boil. Add risoni and cook, stirring often, for 15-20 minutes.
Meanwhile, in a large non-stick frying pan heat olive oil over medium-high. Add chorizo and cook, stirring, for 2-3 minutes, or until golden brown. Add celery and onion and food for 2-3 minutes.
Add the chorizo mixture, beans and spinach to the risoni. Season with cracked black pepper and simmer for 2-3 minutes. Stir through basil.
Divide soup into four bowls and top with besto and extra basil leaves