Preheat the oven to 350F and line a large baking sheet with parchment paper.
Make the meatballs:
In a large skillet, heat the oil over medium heat. Sauté the onions and the two garlic cloves until softened, about 3 minutes.
Transfer the onion mixture inside the bowl of your food processor. Add the quick oats, beans, tomato paste, 2 tablespoons Italian seasoning, salt, and black pepper. Put the lid on and pulse to combine until the beans become part of the coarse mixture. If you don’t have a food processor, use a potato masher to crush the beans into the mixture.
Using your hands, form 12 to 16 balls and place them on the lined baking sheet.
Bake for 15 minutes, carefully flipping them over halfway through.
Make the sauce:
Meanwhile, in a large saucepan or skillet with sides, heat 1 tablespoon of oil over medium heat. Add the remaining garlic and sauté until fragrant, for about 1 minute. Pour the crushed tomatoes, salt (if using), crushed tomatoes, sugar (if using), and Italian seasoning. Simmer on low for 10 to 15 minutes while the meatballs are in the oven.
Once the meatballs are ready, remove them from the oven, transfer them to the tomato sauce, and simmer for 15 minutes.
Cook the pasta:
While the meatballs simmer in the sauce, cook the spaghetti according to the package directions. Drain and set aside.
Serve & Store:
Serve 3 to 4 meatballs with sauce over the spaghetti and sprinkle parmesan cheese on top if desired.
Refrigerate leftovers in an airtight container for up to 4 days or freeze, once cooled, for up to 3 months.
Notes
You can also use old-fashioned or rolled oats for this recipe. I suggest you pulse them a little longer in the food processor to make sure they chop down small enough to absorb the ingredients.