Peel the carrot and chop it in cubes of about 5mm in size; wash and slice the celery stick, the onion, and crush or mince the garlic, as preferred.
In a large pan, which has a lid, put the olive oil and once warm add the garlic, onion, carrots, and celery; mix well and keep on a low-medium flame for a couple of minutes, then add salt and pepper to taste, mix again and put the lid on the pan. Allow the soffritto (or sofrito) to cook for about 5 minutes on a low flame, or until the onions and celery turn golden, the carrots start to soften and the rawness of the garlic has gone.
Once this happens, put the flame to medium-high and, without the lid start adding the minced beef; try and break it down as much as possible, so you’ll be able to brown it properly. Once all the meat is added, mix the beef well and keep on stirring gently until all of it has browned.
OPTIONAL: Once all the minced beef has browned, add the red wine and mix well; keeping the sauce on a medium-low flame, allow the wine to evaporate.
Once the wine has evaporated (or all the minced beef has browned if skipping that step), add the tomato puree and mix well. Allow the tomato puree to gently fry for a couple of minutes before proceeding to the next step.
At this point add the tin of chopped tomato plus 400ml of water, bring to the boil, then bring the flame down to low.
OPTIONAL: Add the sugar, stir well once more, and put the lid back on the pan. This step is necessary only if the tomato sauce or puree are acidic.
Ideally, you will be simmering this for at least one hour on a low flame, during which time you will occasionally stir to ensure the sauce doesn’t dry up or stick (depending on how low your low-flame is).
Remove the lid from the saucepan and allow to continue simmering to bring to the desired consistency. At this stage you can also adjust the levels of salt and add some chopped herbs, if wanted. I, personally, add a bit of parsley sometimes.
Once you are about 20 minutes away from the sauce being ready, put a large pan of water to boil and once the water boils, add the salt and spaghetti and mix well straight away.
Cook the spaghetti for as long as it says on the package (this will mainly depend on the size of the spaghetti – more of this in notes).
Once the spaghetti are al dente, drain them quickly, without over-draining them, and add them to the saucepot.
Mix well the spaghetti and the sauce, divide into six plates and enjoy!