Tomato paste is one of those items that can add richness and body to stews, soups and braises. It's an essential pantry item that will never go away. And while it's easy to buy in tiny supermarket cans, it's worth making your own. Plum tomatoes are ideal, bred for sauce and paste. The most famous varieties are the Italian San Marzano, which have a thin skin and pointed bottom. They're fleshy and have low-water content.
Take five pounds of tomato and roughly chop them. Combine them with ¼ cup extra-virgin olive oil and cook, stirring occasionally, until the tomatoes have released their juices and have become very soft, about 10 minutes. Season with salt and transfer to a food mill and pass the tomatoes through, leaving the seeds behind. Transfer the purée to an oiled sheet tray and bake at 300 degrees, for about 2½ to 3 hours, occasionally stirring and folding the paste onto itself using a rubber spatula so that the water from the tomatoes evaporates and paste takes on a deep red shade. Transfer to an airtight container. Store in the refrigerator and use within a month or freeze and use within six months.