Prawn and chorizo gumbo

Name: Prawn and chorizo gumbo
Ingredients: 2 tablespoon olive oil; 50 gram butter; 2 medium (300g) onions, chopped finely; 4 clove garlic, chopped finely; 1 tablespoon cajun seasoning; 1 teaspoon sweet paprika; 1 teaspoon cayenne pepper; 2 celery stalks (300g), sliced thinly; 1 medium (200g) green capsicum, chopped; 1 long green chilli, sliced thinly; 300 gram chorizo, sliced thinly; 300 gram okra, sliced thinly; 400 gram canned diced tomatoes; 2 tablespoon tomato paste; 2 litre (8 cups) chicken stock; 2/3 cup (130g) medium-grain rice; 12 medium (600g) uncooked prawns, peeled and de-veined; 1/4 cup roughly chopped flat leaf parsley