Cajun meatballs

Name: Cajun meatballs
Ingredients: 2 tbsp butter; 2 tbsp plain flour; 1 onion, finely chopped; 1 green pepper, deseeded and finely chopped; 2 celery sticks, finely chopped; 2 garlic cloves, chopped; 1 bay leaf; 400g can plum tomato; 1 chicken stock cube; dash of Tabasco sauce or hot pepper sauce; 4 spring onions, finely sliced; handful coriander, roughly chopped; rice or mash, to serve; 1 tbsp Cajun seasoning; 500g pack turkey mince; 1 tbsp vegetable oil