How to peel the tomatoes: Poke a hole into the bottom of the tomato with a toothpick. Place the tomato in boiling water for 10 seconds and then the skin should peel off. Immediately place in a bowl and roughly chop.
Cook the garlic in the olive oil on low heat until fragrant. Add the onion and stir-fry on medium heat until transparent. If it seems that it is going to burn, lower the heat to low.
Add the chopped tomatoes, the basil leaves, and the salt to Step 2. Cook on medium heat until it begins to boil. Once boiling, lower the heat to low and let it boil down for 20-30 minutes.
Remove any scum that rises to the surface. Once it has boiled down about 2/3 and has thickened, it's done. (Mine usually finishes in about 25 minutes.)
If you want to store the sauce: Pour the slightly cooled sauce into a sterilized jar and seal tightly with a lid. Once it has cooled completely, store in the refrigerator. It will keep for about 10 days.
Story Behind this Recipe
I make and store this sauce every year during tomato season. If you don't want the seeds in the sauce, you can strain the sauce to remove them. This tomato sauce goes well with anything.
Leave the tomatoes out at room temperature. Since all you have to do is boil, peel and simmer the tomatoes, this is very easy to make. This sauce has a wide variety of uses, such as pasta or simmered tomatoes, and it's very convenient to have stored and ready to use. (You can store it in freezer bags in the freezer as well.) Try making this tomato sauce during the summer.