It's easy to make fresh tomato sauce at home with a couple of pounds of ripe plum tomatoes plus a few more ingredients. And, in a pinch, you can use canned tomatoes instead.
Cut an x on the non-stem end of each tomato with a paring knife.
Bring water to a boil. Blanch the tomatoes for one minute and then move them to an ice bath.
Peel the tomato skins after the tomatoes are cooled. (They should peel off easily.) Once peeled, cut the tomatoes into quarters.
Heat a saucepan over medium heat. Add the olive oil. Once the oil is shimmering, add the chopped onion and sauté until soft and translucent. Add the garlic and cook until fragrant, about one minute. If you choose to add chili flake, stir it in now.
Add the tomatoes to the pan, making sure to scrape everything from the cutting board including the liquid. Turn the heat on low.
Simmer the tomatoes for one hour, stirring about every 10 minutes with a wooden spoon. As you stir, press the tomatoes against the side of the saucepan to help break down the tomatoes. Add a little bit of water to the mixture if it becomes too thick or sticks to the bottom of the pan.
After an hour, the tomatoes should have a pasty, saucy consistency. After adding salt and pepper to taste, tear and mix in the fresh basil. Place a lid over the sauce to keep it warm.
Serve by mixing it with your favorite pasta.
Notes
You can substitute the fresh tomatoes with a 28 oz. can of canned tomatoes or 500 milliliters (approximately one pint) of passata.
You can freeze the sauce in a plastic container for up to six months
You should have enough sauce for one pound of pasta.
You can add herbs like tarragon, parsley or mint instead of basil to create new flavor combinations.