Soak the capers if they come salted; about 15 minutes should do it. If your capers are in brine, just rinse them well under a tap.
For this recipe, if you haven’t found Taggiasca olives, just use any 3-5 good-quality olives per person, depending on the size. If your olives are firm, and have stones, destone them. The best way to do this is to crush each olive, either with the flat side of a knife (as you would when bruising garlic) or with something heavy. Just bash each olive until it’s crushed and pick out the stones.
Fill a large saucepan with water, put the lid on and bring to the boil over a high heat. Don’t forget to season the water with salt. Meanwhile, peel the garlic and squash it lightly with the flat side of a knife. It should be gently bruised or cracked, but if you are heavy-handed and squash it too clumsily, it will still be okay. Finally, cut the tomatoes in half across the middle.
Put a large saucepan over a medium-low heat and add the oil. Add the cracked/squashed garlic cloves and chilli flakes and give them a swirl around the pan so the garlic cloves get covered in oil. Cook for 3-5 minutes over a low heat, stirring from time to time. You want the garlic to release its flavour but not burn or colour too much at all.
When the garlic begins to become ever so slightly golden, add the anchovies and 1 tsp of their oil. Keep frying gently, prodding the anchovies from time to time until they dissolve in oil. Then, gently ‘scrunch’ in the tomatoes to help them release a bit of their juice, increase the heat, add the sugar and stir.
Put the lid on, reduce the heat right down to its lowest level and put the spaghetti into the boiling salted water. The sauce will be ready by the time your pasta is perfectly al dente for the next step (this is usually 3-4 minutes less than the advised cooking time – it should be bendy but still have a bit of a bite).
When the pasta is nearly ready, add the capers and olives to the sauce and remove the garlic; always keep the lid on.
Scoop out a cupful of the pasta water. Drain the almost-done spaghetti, then transfer the pasta to the pan of sauce and stir well. Add a splash of pasta cooking water, increase the heat and agitate the pasta in the sauce. Let the sauce boil and the pasta finish cooking in the sauce for 2-3 minutes. Taste the pasta: it should still be firm of course, but not as toothy as before. Serve with plenty of grated parmesan over the top.