Add finely chopped garlic to the oiive oil and heat until fragrant.
Add thinly sliced onion. When it's absorbed the oil, set the heat to low-medium, and sauté the onion until it's caramelized. (Turn the heat down to low when you aren't stirring it.)
Add canned tomatoes and the ◎ ingredients. Cover with a lid and simmer over low heat for 30 minutes to an hour. Taste, adjust the seasoning with salt and pepper, and it's done.
You can use it as-is (as show in the photo), or puree it in a blender until smooth.
Story Behind this Recipe
I love Chef Mamoru Kataoka's recipe and read that he sweats onions slowly for 1 hour. Up until then I made tomato sauce without cooking the onion for that long, but I tried it and I was struck by the difference in the depth of flavor of the sauce.
If you sauté the onion slowly until a lot of flavor seeps out, you can make a delicious sauce without having to add a soup stock cube. Stirring the pot slowly while you're surrounded by the fragrance of the onion is a nice experience.