Adding the Tomatoes: Infusing the Sauce with Freshness. Pour the prepared tomatoes into the saucepan and bring to a simmer. Season with salt, pepper, and a pinch of sugar to balance the acidity. Allow the sauce to simmer gently for at least 30 minutes, or up to several hours, stirring occasionally.This will allow the flavors to meld and the sauce to thicken. More @Wikipedia
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