Heat the olive oil in a large saucepan over medium heat and add the diced onion. Sauté for about 5-7 minutes or until the onion is translucent.
Add the diced garlic and sauté for another 2 minutes or until fragrant.
Add the tomato paste, and mix well, scraping any browned bits off the bottom of the pan. After the paste darkens, add in the Italian seasoning, thyme, oregano, and red pepper flakes. Mix well.
Stir in the tomato sauce, diced tomatoes, brown sugar, bay leaf, basil, and salt and pepper to taste.
Bring to a simmer and then turn the heat down to low. At a minimum, simmer for 25 minutes, but really this sauce should be simmered for at least an hour or two.
Once it's done, use it on any of your favorite dishes like spaghetti, pasta, pizza, or as a marinara dip. Top with fresh basil if desired.
