Meatballs are the kind of thing you really don't need a recipe to make. You do need:
1. Some meat. About a pound of it. (Higher fat is best, but if you're using meat with a lower fat content -- or not dark poultry meat -- you'll need to add a bit of extra seasoning.)
2. Something to bind the meat. (eggs, breadcrumbs, maybe tomato paste)
3. Seasoning (Start with onions and/or shallots, and build from there.)
1. Cook a small onion or some shallots in oil.
2. Mix everything together.
So that's meat, cooled onions, maybe a spoonful of tomato paste, a cup of any salty cheese like pecorino, a cup of breadcrumbs, a bit of milk, and an egg. If it feels too wet, add more breadcrumbs and/or cheese. If you have some parsley or oregano and people who don't freak out about green stuff in their meatballs, chop some and add.