Heat the olive oil on a medium heat in a pan with a large surface area (such as a large frying pan or cast iron pan), then add the sliced garlic. Cook for a couple of minutes without browning the garlic.
Add the chopped tomatoes, basil and salt and pepper to the pan. Half fill the empty tomato can with water and add that to the pan, too. If using, also add the pinch of red pepper flakes/chili.
Let the sauce simmer for 20 to 30 minutes, or until the sauce has thickened and reduced to your liking (it shouldn't be too watery, or too thick).
Taste the sauce, then adjust the seasoning if necessary. Also stir in the sugar/honey (if you like) and the balsamic vinegar.
