First, I like to cut up the onions and garlic and place them in a bowl. You want minced garlic and small dice for the onions.
Next, add in the breadcrumbs and cheese. I use Pecorino Romano, but you can use Parmesan. I also use Panko breadcrumbs, but you can use Italian instead. It's really whatever you prefer. At this point, I also add in the seasoning and red pepper.
Next, I add in the herbs. Fresh parsley and basil here.
Add in the whole egg and give it a mix.
Add the beef. I use ground chuck. Mix it until just combined. Don't overmix.
Use an ice cream scoop to scoop out the meat and roll between the palms of your hands into a ball. Place on a greased baking sheet and bake at 375°F and bake it for about 10-13 minutes.
Once cooked, remove from oven.
I like to finish cooking the meatballs in whatever sauce I'm eating with them. In applications like Spaghetti or meatball subs, I always cook them in sauce. Not for long, just a minute or so.