Add onion, olive oil, onion and garlic to a 5-quart saucepan. Cover and cook until onion is soft, stirring occasionally.
Add tomatoes, basil, oregano, salt, pepper and sugar and stir to combine.
Bring the mixture to a boil, then reduce the heat and simmer for 20 minutes, stirring occasionally with a wooden spoon, breaking up the tomatoes into smaller pieces.
Transfer the mixture to a blender, or use an immersion blender and blend until smooth (note this is optional if you like a chunkier sauce).
Serve on top of your favorite pasta, tortellini, etc.
Video
Notes
Ingredient Notes/Substitutions
Onion. I suggest a sweet white or yellow onion for the best results.
Minced garlic. Use freshly minced or jarred.
Olive oil. I really don't recommend substitutes, but if you must, avocado oil is the next best choice.
Whole Peeled Tomatoes. I use canned tomatoes for ease - to use fresh tomatoes, you need to boil and peel the tomatoes, then use in this recipe as directed.
Dried oregano. you can substitute 1 teaspoon dried oregano with 1 Tablespoon fresh oregano.
Granulated sugar. honey is a good substitute for sugar. This just helps cut the acidity of the marinara sauce, it does not make the sauce sweet.
StoreStore leftover sauce in a glass jar in the refrigerator for up to 2 weeks.FreezeFreeze leftover sauce in a glass jar (make sure to leave some room at the top because the sauce expands in the freezer), for up to 6 months. Thaw in the refrigerator overnight or at room temperature, reheat on the stovetop.