Preheat the oven to 220 degrees Celsius.
Cut the puff pastry into 12 rectangles and place 6 of them on a baking sheet lined with baking parchment. Cover with another sheet of parchment and place another baking sheet on top - this will stop the pastry rising as it cooks. Place the remaining 6 pastry rectangles on another baking sheet but do not cover - this will allow the pastry to rise as it cooks. Transfer both baking sheets to the oven and cook for 15 minutes until golden brown.
Remove the head and shell from the prawns. Make an incision along the spine of each prawn with a sharp knife and remove the black vein.
Chop the spring onion. Roughly chop the herbs. Peel and finely chop the garlic.
Cook the green beans in salted boiling water for 3 minutes. Whilst they are cooking, heat the olive oil in a frying pan. Season the prawns, add to the pan and cook for 3 minutes. When cooked, add the garlic, herbs and a squeeze of lemon juice.
To assemble the dish, place the flat pastry rectangle on a plate. Top with the green beans and then the prawns before placing the second puff pastry rectangle on top. Drizzle any remaining herbs and olive oil around the plate and serve with a handful of rocket leaves.
«This recipe can also be made using smaller prawns - simply adjust the cooking time to suit.»