This is a very quick recipe to prepare as the pasta sauce will take the same time to cook as spaghetti. Start this recipe by bringing a large pan of salted water to the boil and cook the spaghetti. Meanwhile, you can prepare the pasta sauce by heating the olive oil and butter in a large frying pan. Add in the pancetta and cook for 2 minutes to brown all over. Add in the chopped garlic, onion and red chilli. Season well with salt and pepper and cook for a further 4 minutes to soften the onion. Place the tomatoes in a bowl of hot water for 30 seconds, then discard the water and peel off the skins. Next, cut the tomatoes in half and remove any seeds. Chop the tomatoes into small cubes and add them to the pan. Cook the tomatoes for just 2 minutes before adding the black olives, capers, wine and seafood to the pan. Cover the pan with a lid and continue to cook for 4-5 minutes, or until the mussels have opened and the seafood is just cooked. Squeeze in the lemon juice, add the chopped basil and stir the sauce well. Add the cooked spaghetti to the sauce and toss around in the pan to coat all over with the juices. Serve the seafood spaghetti immediately into deep pasta bowls garnished with fresh basil leaves.