Chop onions and carrots, peel garlic, and mince basil. (Don’t worry about the exact size of the cut since the sauce will be blended.)
Preheat a 3-quart Dutch oven over medium heat and add olive oil.
Add onions and carrots to the pot. Saute for a few minutes until onion begins to soften.
Smash garlic and add it to the pot. Saute until fragrant and add tomatoes.
Add bay leaves, oregano, sugar, and salt. Stir well, cover with a lid but leave a crack for steam to escape.
Cook for about 30 minutes and add minced basil leaves. Stir and cook for another 30 minutes or so.
Before blending the sauce, make sure to remove the bay leaves.
Blend sauce in the blender (or using an immersion blender) until smooth. Make sure to open the little tab so the steam can escape while blending. (Be careful, you are dealing with scalding-hot sauce. Make sure to use a blender that is meant for hot foods as well.)
If not using right away, keep in the refrigerator, in a glass jar with a lid for 4-7 days.
(Check the post for storing and freezing instructions.)
Video
Notes
Storing: Store spaghetti sauce in a glass jar (or two jars) with a lid for 4-7 days. Keep it in the refrigerator. (Note, there is more information in the post.)
Reheating: you can reheat individual portions in a microwave for about 30 seconds at a time, stirring in between. If you want to reheat all the sauce at the same time, do so in the sauce pot over medium-low heat. Keep the sauce pot covered with a lid to help with splatter. Remember, you can always mix in some cold sauce with hot pasta to cool down the pasta and heat up the sauce at the same time.