Start this recipe by putting the cubed aubergine on a baking tray and drizzle with 1 tablespoon of olive oil. Season well with salt and pepper and bake in the oven at 200`c for 15-20 minutes. Meanwhile, heat up the remaining oil in a large pan and gently fry the garlic and onion together for 3-4minutes. Add in the chopped anchovies, polpa, black olives and season well with salt and pepper. Turn down the heat and leave the sauce to cook and reduce down for 20 minutes. You may add a little water if the sauces becomes too dry. Whilst the sauce is cooking, you can also cook the spaghetti in a large pan of salted boiling water. When you are ready to serve, ad the chopped basil to the pasta sauce and mix well. Divide the cooked pasta into your serving bowls and pour over the sauce. Decorate with a few fresh basil leaves and serve.