Peel the prawns and remove the intestinal tract, keeping the shells for the stock. Marinade the prawns in the juice of half the lemon, 1 bay leaf and pinch of salt and pepper.

To make the stock, add the shells to a small saucepan with 500ml water, a bay leaf, a slice of onion, and a good pinch of thyme and oregano.

Once the prawns have marinated, dust the prawns in flour and heat the butter and the oil in a pan.

Sauté the finely chopped onion until soft and golden. Add the garlic and the parsley and continue to cook on a low heat for a further 2 minutes.

Add the prawns to the pan, and cook over a medium heat, co until lightly browned on both sides.

Add the wine and continue to cook until the wine has almost reduced, then add the stock and the tomato and simmer until the prawns are cooked, and the sauce has thickened. Add juice from the second half of the lemon to balance the flavours if necessary, and season with salt and pepper.