If you think your favorite dishes taste great with tomato paste from a can, wait until you try them with homemade. There's nothing like that zesty burst of flavor from the tomato paste you have made from scratch.
Score a ring around each tomato, carefully cutting only the skin, not the flesh.
Blanche the tomatoes in a big boiling pot of water for 15 to 30 seconds. Put them in an ice cold water bath to cool them down, or allow them to cool on their own.
Peel the skin off the tomatoes. It should fall off easily.
Core the tomatoes, removing all the seeds, which you may want to save for a dressing, soup or salad.
Dice the tomatoes and put them back in the pot (be sure you've emptied it of all water). Add salt and simmer on medium-low heat for about 1 hour. Keep an eye on your tomato paste mixture, stirring frequently to prevent sticking.
Pour the tomatoes into a metal colander sieve inside a large bowl. The juice of the tomatoes will pour right through into the bowl, but you'll need to use a spatula or wooden spoon to press the tomato flesh through. When it sticks to the bottom of the sieve without falling into the bowl, use the spatula to scrape it off.
Return the tomatoes to the pot and add the basil, oregano and sage. Cook on medium heat for another couple of hours, or until it has that thick paste consistency that sticks to a spoon.
Add the canola or extra virgin light olive oil to the paste and stir well.
Cook with your tomato paste immediately or store it in the refrigerator for up to three days. For longer storage, try freezing it in a freezer-safe container or plastic bag.