Preheat the grill to high.
Heat the oil in a flameproof casserole over a medium heat, add the onion and cook for 5 minutes until soft and translucent, then add the garlic, chilli and seasoning and cook for 2 minutes to colour and infuse their flavour.
Toss in the caraway and nigella seeds with the oregano and stir into the onions for 1 minute before adding the tomatoes, tomato purée, honey and feta. Cover and cook for 12 minutes until the tomatoes have fully broken down and the feta has melted into the sauce. Add a splash of water if it sticks to the bottom of the pan.
Uncover the pan and stir so that all the ingredients combine with the sauce, then add the green leaves and basil, reserving a few basil leaves to garnish, and stir for 2 to 3 minutes or until the greens have wilted.
Add the beans to the sauce and place the prawns on top. Simmer for 2 minutes then transfer to the grill for 4 minutes to finish cooking the prawns and caramelise the top of the dish.
Garnish with the reserved basil leaves and serve.
For a smoother sauce, blend the chilli, garlic and onion in a small processor before cooking.
For even more flavour, toast the caraway and nigella seeds for 1–2 minutes and crush in a pestle and mortar before adding.