Smoky spanish prawns and spaghetti

Prawn-flavoured stock preparation. This step can be done in advance: Shell and remove the heads of the large prawns. Place the heads and shells in a bowl and add 1tbsp olive oil. Heat a a large saucepan, and add the prawn heads and shells, frying until they turn pink, and give off a lovely prawn aroma. Add 1 litre of water, and bring to the boil. Add strands of saffron, and a squirt of tomato puree. Reduce heat and simmer for about 30 minutes. Strain and retain the liquid, discarding the prawn solids.

Bring the pan of prawn stock up to a boil, and add spaghetti. Meanwhile, finely chop the onion and fry in a wok or deep frying pan. Add garlic when the onions soften, and fry for a further couple of minutes. Add a glug of cheap white wine, and cook until reduced. Add half of the sliced tomatoes, the parsley, lemon zest and dried oregano. Add a ladleful of the spaghetti cooking water and cook until slightly reduced. Then add all of the prawns, the smoked paprika and the rest of the tomatoes. Add salt and pepper to taste.

Just before the spaghetti is cooked, add some salt to the cooking water. When cooked, drain and add to the prawn sauce. Serve with a little grated Parmesan if desired.