Cut mozzarella sticks into quarters and freeze pieces for about 30 minutes.
Meanwhile, add Parmesan, garlic, and green onions to a little food chopper or food processor and blend until finely ground.
In a separate large bowl, combine ground beef, Parmesan cheese mixture, almond flour, Italian seasoning, salt, pepper, and egg. (Note: If your meatballs aren't sticking together well, just add another egg -- depending on the size of your eggs, the amount of ground beef, or who knows what, my meatballs sometimes use one & sometimes take two.)
Line two rimmed cookie sheets with parchment paper or silicone baking mats.
Flatten ground beef mixture into 16 disks, spaced evenly across both cookie sheets.
Place one piece of mozzarella in the middle of each and roll into a ball, covering the cheese completely on all sides.
Bake at 375 degrees for 25 minutes or until meatballs are cooked through, flipping your cookie sheets around halfway through.
Notes
These are also gluten free, for those of you looking to make meatballs without breadcrumbs.