Preheat oven to 400. Line a large rimmed cookie sheet with parchment paper.
Mix together all the ingredients. Form into balls and place on the cookie sheet.
Bake for 18-20 minutes until golden brown and cooked through. They should reach 160 on a meat thermometer.
Notes
Substitutions: swap the meat for ground turkey, chicken, or beef. You can also exchange the mozzarella for any other cheese that you like. Just shred it before adding it to the mix. Prep Time: make the meatballs and put them in the fridge for up to one day in advance before baking. To Reheat: place the meatballs on a baking sheet and cook for 350 degrees for 10-15 minutes or until they are hot. You can microwave them as well, but they may dry out some. To Freeze: layer the meatballs on a baking sheet and flash freeze. Once frozen, put them in a freezer bag or container. This will keep them from sticking together. Thaw in the fridge and reheat before serving.