Put the pasta sauce and stock into a large saucepan, bring to the boil and simmer for 2-3 mins. Add the courgettes and fennel and simmer for 2 mins.
Cut the hoki fillets into 4cm pieces. Add to the soup and poach over a low heat for 2-3 mins or until the fish is cooked. Don’t stir too often or the fish will break up. Gently stir in the basil and adjust the seasoning.
Mix the chipotle chilli mix or chilli paste with the crème fraîche and season. Ladle the soup into bowls and spoon a dollop of crème fraîche on top.