Add onion, butter, and tomatoes - with their juices - into a large pot, bring to a boil, then allow to simmer for 75 minutes. Season with salt.
Add all meatball ingredients into a bowl, mix well. Use a disher to roll even sized meatballs, set aside.
After allowing sauce to simmer for 75 minutes or so, add in your raw meatballs into the sauce, allow them to cook through for ~30 minutes or so, occasionally turning over meatballs in sauce so all sides cook fully through.
Meanwhile, cook one pound of pasta of choice, add to your sauce. Top with fresh parsley, grated parmesan, and crushed red pepper flakes, if desired.