Heat the olive oil over medium heat and sauté the onion for about 5 minutes. When it starts becoming translucent, add the garlic and sauté another 5 minutes.
Increase heat to high and add the tomatoes/tomato sauce and tomato paste. Stir well to incorporate the paste.
Add the optional sugar, then bring to a boil. Lower heat, add the pepper and herbs, cover, and let simmer for at least 15 minutes, stirring occasionally. If you have time, let it simmer for an hour or more – the sauce will just keep getting better.
Note: be very careful when you lift the lid – boiling sauce may splash your hands.
Taste and adjust seasonings. If the sauce is too thick, you can add some water.
Discard the bay leaf and serve.