Prepare the onion and chop it coarsely.
Heat the extra virgin olive oil in a large saucepan over low heat for a couple of minutes, add the onion and the unpeeled garlic.
Sauté them gently and when the onion is a little golden, remove the garlic and add the canned tomatoes.
In the meantime, wash the fresh tomatoes and dice them without removing the skins. Add them to the saucepan and mix the ingredients with a wooden spoon.
Add a little salt and the sugar.
Cover the pan partially with the lid. Check the flame: make sure it’s low enough because it’s essential not to burn the sauce as it would leave an unpleasant bitter aftertaste.
When the sauce looks homogeneous and the tomatoes are completely softened, turn off the heat and mix the ingredients using an immersion blender.
Then, use a fine mesh strainer and filter the sauce in order to separate skins, seeds, and tomato scraps.
Put the sauce back on the stove and continue to let it thicken without the lid over a low heat. Taste the sauce and add salt if necessary.
If you want to make la pasta al pomodoro, boil the water, add a handful of salt and the pasta, and cook it following the package instructions.
When the pasta is cooked, drain and add it to the nonstick skillet where you have just prepared the sauce. Toss well and serve it hot.